*255Doris, J.

Ernest P. Ardente, the plaintiff, brought this civil action in Superior Court to specifically enforce an agreement between himself and William A. and Katherine L. Horan, the defendants, to sell certain real property. The defendants filed an answer together with ia motion for summary judgment pursuant to Super. R. Civ. P. 56. Following the submission of affidavits by both the plaintiff and the defendants and a hearing on the motion, judgment was entered by a Superior Court justice for the defendants. The plaintiff now appeals.

In August 1975, certain residential property in the city of Newport was offered for sale by defendants. The plaintiff made a bid of $250,000 for the property which was communicated to defendants by their attorney. After defendants’ attorney advised plaintiff that the bid was ac*256ceptable to defendants, he prepared a purchase and sale agreement at the direction of defendants and forwarded it to plaintiff’s attorney for plaintiff’s signature. After investigating certain title conditions, plaintiff executed the agreement. Thereafter plaintiff’s attorney returned the document to defendants along with a check in the amount of $20,000 and a letter dated September 8, 1975, which read in relevant part as follows:

“My clients are concerned that the following items remain with the real estate: a) dining room set and tapestry wall covering in dining room; b) fireplace fixtures throughout; c) the sun parlor furniture. I would appreciate your confirming that these items are a part of the transaction, as they would be difficult to replace.”

The defendants refused to agree to sell the enumerated items and did not sign the purchase and sale agreement. They directed their attorney to return the agreement and the deposit check to plaintiff and subsequently refused to sell the property to plaintiff. This action for specific performance followed.

In Superior Court, defendants moved for summary judgment on the ground that the facts were not in dispute and no contract had been formed as a matter of law.1 The trial justice ruled that the letter quoted above constituted a conditional acceptance of defendants’ offer to sell the property and consequently must be construed as a counteroffer. Since defendants never accepted the counteroffer, it followed that no contract was formed, and summary judgment was granted.

Summary judgment is a drastic remedy and should be *257cautiously applied; nevertheless, where there is no genuine issue as to any material fact and the moving party is entitled to judgment as a matter of law, summary judgment properly issues. Ladouceur v. Prudential Ins. Co., 111 R.I. 370, 302 A.2d 801 (1973). On appeal this court is bound by the same rules as the trial court. Cardente v. Travelers Ins. Co., 112 R.I. 713, 315 A.2d 63 (1974). With these rules in mind we address ourselves to the facts.

The plaintiff assigns several grounds for appeal in his brief. He urges first that summary judgment was improper because there existed a genuine issue of fact. The factual question, according to plaintiff, was whether the oral agreement which preceeded the drafting of the purchase and sale agreement was intended by the parties to take effect immediately to create a binding oral contract for the sale of the property.

We cannot agree with plaintiff’s position. A review of the record shows that the issue was never raised before the trial justice. The plaintiff did not, in his affidavit in opposition to summary judgment or by any other means, bring to the attention of the trial court any facts which established the existence of a relevant factual dispute. Indeed, at the hearing on the motion plaintiff did not even mention the alleged factual dispute which he now claims the trial justice erred in overlooking. The only issue plaintiff addressed was the proper interpretation of the language used in plaintiff’s letter of acceptance. This was solely a question of law. See Cassidy v. Springfield Life Ins. Co., 106 R.I. 615, 262 A.2d 378 (1970); Johnson v. Kile & Morgan Co., 49 R.I. 99, 140 A. 3 (1928).

It is well-settled that one who opposes a motion for summary judgment may not rest upon the mere allegations or denials of his pleading. He has an affirmative duty to set forth specific facts which show that there is a genuine issue of fact to be resolved at trial. If he does not do so, *258summary judgment, if appropriate, will be entered against him. Gallo v. National Nursing Homes, Inc., 106 R.I. 485, 488, 261 A.2d 19, 21 (1970); Sutter v. Harrington, 51 R.I. 825, 154 A. 657 (1931); 1 Kent, R. I. Civ. Prac. §56.4 (1969). Accordingly, since no genuine issue of fact was presented to the trial justice, we hold that he did not err in ruling that summary judgment was appropriate.2

The plaintiff’s second contention is that the trial justice incorrectly applied the principles of contract law in deciding that the facts did not disclose a valid acceptance of defendants’ offer. Again we cannot agree.

The trial justice proceeded on the theory that the delivery of the purchase and sale agreement to plaintiff constituted an offer by defendants to sell the property. Because we must view the evidence in the light most favorable to the party against whom summary judgment was entered, in this case plaintiff, we assume as the trial justice did that the delivery of the agreement was in fact an offer.3

The question we must answer next is whether there was an acceptance of that offer. The general rule is that where, *259as here, there is an offer to form a bilateral contract, the offeree must communicate his acceptance to the offeror before any contractual obligation can come into being. A mere mental intent to accept the offer, no matter how carefully formed, is not sufficient. The acceptance must be transmitted to the offeror in some overt manner. Bullock v. Harwich, 158 Fla. 834, 30 So.2d 539 (1947); Armstrong v. Guy H. James Constr. Co., 402 P.2d 275 (Okla. 1965); 1 Restatement Contracts §20 (1932). See generally 1 Corbin, Contracts §67 (1963). A review of the record shows that the only expression of acceptance which was communicated to defendants was the delivery of the executed purchase and sale agreement accompanied by the letter of September 8. Therefore it is solely on the basis of the language used in these two documents that we must determine whether there was a valid acceptance. Whatever plaintiff’s unexpressed intention may have been in sending the documents is irrelevant. We must be concerned only with the language actually used, not the language plaintiff thought he was using or intended to use.

There is no doubt that the execution and delivery of the purchase and sale agreement by plaintiff, without more, would have operated as an acceptance. The terms of the accompanying letter, however, apparently conditioned the acceptance upon the inclusion of various items of personalty. In assessing the effect of the terms of that letter we must keep in mind certain generally accepted rules. To be effective, an acceptance must be definite and unequivocal. “An offeror is entitled to know in clear terms whether the offeree accepts his proposal. It is not enough that the words of a reply justify a probable inference of assent.” 1 Restatement Contracts §58, comment a (1932). The acceptance may not impose additional conditions on the offer, nor may it add limitations. “An acceptance which is equivocal or upon condition or with a limitation is a counter*260offer and requires acceptance by the original offeror before a contractual relationship can exist.” John Hancock Mut. Life Ins. Co. v. Dietlin, 97 R.I. 515, 518, 199 A.2d 311, 313 (1964). Accord, Cavanaugh v. Conway, 36 R.I. 571, 587, 90 A. 1080, 1086 (1914).

However, an acceptance may be valid desipite conditional language if the acceptance is clearly independent of the condition. Many cases have so held. Williston states the rule as follows:

“Frequently an offeree, while making a positive acceptance of the offer, also makes a request or suggestion that some addition or modification be made. So long as it is clear that the meaning of the acceptance is positively and unequivocally to accept the offer whether such request is granted or not, a contract is formed.” 1 Williston, Contracts §79 at 261-62 (3d ed. 1957).

Corbin is in agreement with the above view. 1 Corbin, supra §84 at 363-65. Thus our task is to decide whether plaintiff’s letter is more reasonably interpreted as a qualified acceptance or as an absolute acceptance together with a mere inquiry concerning a collateral matter.

In making our decision we recognize that, as one text states, “The question whether a communication by an offeree is a conditional acceptance or counter-offer is not always easy to answer. It must be determined by the same common-sense process of interpretation that must be applied in so many other cases.” 1 Corbin, supra §82 at 353. In our opinion, the language used in plaintiff’s letter of September 8 is-not consistent with an absolute acceptance accompanied by a request for a gratuitous benefit. We interpret the letter to impose a condition on plaintiff’s acceptance of defendants’ offer. The letter does not unequivocally state that even without the enumerated items plaintiff is willing to complete the contract. In fact, the letter seeks “confirmation” that the listed items “are a part of *261the transaction”. Thus, far from being an independent, collateral request, the sale of the items in question is explicitly referred to as a part of the real estate transaction. Moreover, the letter goes on to stress the difficulty of finding replacements for these items. This is a further indication that plaintiff did not view the inclusion of the listed items as merely collateral or incidental to the real estate transaction.

Manning, West, Santaniello & Pari, Joseph T. Pari, for plaintiff.

Moore, Virgadamo, Boyle & Lynch, Ltd., Jeremiah C. Lynch, Jr., Joseph R. Palumbo, Jr., for defendants.

A review of the relevant case law discloses that those cases in which an acceptance was found valid despite an accompanying conditional term generally involved a more definite expression of acceptance than the one in the case at bar. E.g., Moss v. Cogle, 267 Ala. 208, 101 So.2d 314 (1958); Jaybe Constr. Co. v. Beco, Inc., 3 Conn. Cir. Ct. 406, 216 A.2d 208, 212 (1965); Katz v. Pratt Street Realty Co., 257 Md. 103, 262 A.2d 540 (1970); Nelson v. Hamlin, 258 Mass. 331, 155 N.E. 18 (1927); Duprey v. Donahoe, 52 Wash.2d 129, 323 P.2d 903 (1958).

Accordingly, we hold that since the plaintiff’s letter of acceptance dated September 8 was conditional, it operated as a rejection of the defendants’ offer and no conctractual obligation was created.

The plaintiff’s appeal is denied and dismissed, the judgment appealed from is affirmed and the case is remanded to the Superior Court.

Mr. Justice Paolino did not participate.

*1186AINSWORTH, Circuit Judge:

This is an appeal from a Mississippi diversity action in which appellant Houston Dairy, Inc. attempted to recover $16,000 sent to appellee John Hancock Mutual Life Insurance Company as a “Good Faith Deposit” on a loan application which Houston Dairy claims never became binding. At the conclusion of the nonjury trial, the district court ruled that there was a binding contract between the parties and that the $16,-000 deposit represented valid, liquidated damages forfeited by Houston Dairy when it breached the contract. We reverse.

I. Facts

John Hancock mailed a commitment letter to Houston Dairy on December 30, 1977 in which it agreed to lend Houston Dairy $800,000 at 9V!i% provided that within seven days Houston Dairy would return the commitment letter with a written acceptance and enclose either a letter of credit or a cashier’s check in the amount of $16,000. The commitment letter stated the $16,000 was a “Good Faith Deposit” and was the appropriate measure of liquidated damages to be awarded John Hancock should Houston Dairy default. Dr. Dyer, president and principal shareholder of Houston Dairy, did not execute the letter until eighteen days later, on January 17, 1978. Along with the letter, Houston Dairy mailed a $16,000 cashier’s check.

Upon receiving the returned commitment letter on January 23, an agent for John Hancock mailed the cashier’s check to the John Hancock Depository and Service Center in Champaign, Illinois, for deposit and sent the loan-closing attorney, Harvey Henderson, the necessary information to close the loan. Meanwhile, Dr. Dyer delivered a copy of the commitment letter to Houston Dairy’s attorney and asked him to call Henderson to ascertain his fee for closing the loan. On January 28, the two attorneys talked and agreed to the method they would use to close the loan and the manner in which the fee would be charged. However, on January 30, Houston Dairy was able to obtain a 9% loan from a state bank. Houston Dairy then requested a refund of its $16,000 deposit, which was refused by John Hancock.

In the district court, Houston Dairy contended that the return of the commitment letter constituted a counter offer since the seven-day time period for acceptance had expired, that John Hancock never communicated its acceptance of the counter offer, thus allowing Houston Dairy to revoke the counter offer, which it did on January 31. Therefore, the argument proceeds, no contract was ever formed and Houston Dairy was entitled to a refund of $16,000.

The district court disagreed, finding that John Hancock had both waived the seven-day limitation and validly accepted a counter offer. Accordingly, the court held that the parties had entered into a binding contract and awarded John Hancock the $16,-000 deposit as valid, liquidated damages for breach of the loan agreement.

II. Was there a contract?

It is fundamental that a contract is formed only upon acceptance of an offer. Couret v. Conner, 118 Miss. 598, 79 So. 230, 232 (1918). Just as basic is the principle that an offeror is free to limit acceptance to a fixed time period. 1 A Corbin, Contracts § 35 (1963); 1 S. Williston, Contracts § 76 (3d ed. W. Jaege, 1957); Restatement of Contracts § 40 (1932). Once the time period has expired, a belated attempt to accept would be ineffective. However, such an untimely attempt to accept normally constitutes a counter offer which would shift the power of acceptance to the original offeror. 1 Corbin § 74; 1 Williston §§ 53, 93; Restatement § 73. Additionally, acceptance of a counter offer is established only by conforming to the rules governing acceptance, not a separate theory of “waiver and ratification.” Kurio v. United States, 429 F.Supp. 42, 64 (S.D.Tex.1970).1

*1187It is therefore clear in the instant case that upon expiration of the seven-day time period, John Hancock’s offer terminated. Thus the action taken by Houston Dairy in signing and returning the commitment letter subsequent to the termination of the offer constituted a counter offer which John Hancock could accept within a reasonable time.

In Mississippi, the courts have long recognized that for acceptance to have effect, it must be communicated to the proposer of the offer. See Pioneer Box Co. v. Price Veneer & Lumber Co., 132 Miss. 189, 96 So. 103, 105 (1923). John Hancock contends it did accept Houston Dairy’s counter offer and that the acceptance was communicated to Houston Dairy.

According to John Hancock, depositing Houston Dairy’s check was itself sufficient to operate as communication of its acceptance of the counter offer. John Hancock argues that its silence plus retention of Houston Dairy’s money constituted acceptance and notification. Indeed, Mississippi has specifically recognized the validity of acceptance by silence within the guidelines laid down in Restatement § 72.2 See Old Equity Life Insurance Co. v. Jones, 217 So.2d 648, 651 (Miss.1969); Ammons v. Wilson & Co., 176 Miss. 645, 170 So. 227, 228 (1936). However, the present facts do not fit within these guidelines. Houston Dairy neither had previous dealings nor had otherwise been led to understand that John Hancock’s silence and temporary retention of its deposit would operate as acceptance. In addition, Houston Dairy had no knowledge that its check had been deposited in John Hancock’s depository. Since Houston Dairy sent a cashier’s check, it could not have known the check had even been deposited unless notified by John Hancock or its bank. No such notice arrived from John Hancock and none is required from the bank.

The Mississippi Supreme Court held in L. A. Becker v. Clardy, 96 Miss. 301, 51 So. 211 (1910) that the mere depositing of a check was insufficient to constitute acceptance of an offer. There, an offeror sent a $100 downpayment along with its order for merchandise to the offeree. As was its policy, the offeree immediately deposited the check in its account, which was later paid in due course by the bank upon which the check was drawn. However, the offeree subsequently mailed a letter to the offeror rejecting the offer and enclosed a check for $100. The court held that upon receipt of the order and downpayment, the offeree was “entitled to a reasonable time in which to examine and determine whether it would accept or reject [the order], ... Deposit*1188ing the check for collection, therefore, did not constitute acceptance of the order.” Id., 51 So. at 213.3

John Hancock also contends that Houston Dairy was notified of its acceptance in the conversation between the attorneys for both parties on January 28. However, a review of the testimony concerning that conversation shows no communication of acceptance. Indeed, John Hancock’s closing attorney testified that at the time of his conversation with Houston Dairy’s attorney, he had not received the executed commitment letter and had no knowledge a counter offer had even been made. His conversation only concerned the method to be used to close the loan and the distribution of the fee to be charged, not acceptance of the counter offer. Houston Dairy cannot be deemed to have knowledge of John Hancock’s acceptance simply by requesting and receiving information on the procedures for closing a loan should an agreement be reached.

III. Conclusion

In summary, Houston Dairy could not accept John Hancock’s offer once the time period had lapsed. Thus, when Houston Dairy executed and returned the commitment letter several days late, it was proposing a counter offer which John Hancock could either accept or reject. Since the actions and policies of John Hancock were unknown to Houston Dairy, mere silence was not operative as an acceptance of the counter offer, no communication of acceptance having been received. Houston Dairy therefore was entitled to revoke its counter offer, which it did on January 31. Accordingly, we reverse the judgment of the district court and render in favor of Houston Dairy for the amount of its deposit, $16,000.

REVERSED.