Once a lease expires and the tenant remains in possession of the premises, the landlord may elect to treat the tenant as a trespasser, Hallett v. Barnett, 51 Colo. 434, 436, 118 P. 972, 973 (1911), or may waive the wrong of holding over and continue the tenancy. Ochsner v. Langendorf, 115 Colo. 453, 456, 175 P.2d 392, 394 (1946); Mattas Motors, Inc. v. Heritage Homes of Nebraska, Inc., 749 P.2d 458, 460 (Colo.App. 1987). In the latter case, and in the absence of a new agreement, the law implies a new contract between the parties based upon the same terms and conditions as the expired lease.

But whether the instrument is considered an assignment or a sublease, is immaterial insofar as the right of Herlacher to assign or sublease to D.A.C. is concerned — in the absence of express prohibition, he had the right to do either. Ochsner v. Langendorf, 1946, 115 Colo. 453, 175 P.2d 392; Sinclair Refining Co. v. Clay, 102 F. Supp. 732, supra; Leslie v. Sherman, 1943, 157 Kan. 157, 139 P.2d 133; Stone v. Martin, 1947, 185 Tenn. 369, 206 S.W.2d 388; 1130 President St. Corp. v. Bolton Realty Corp., 1950, 198 Misc. 198, 97 N.Y.S.2d 422; Patterson v. Butterfield, 1928, 244 Mich. 330, 221 N.W. 293. It must be held then, that the agreement of August 1, 1955, is a valid lease and gave to Herlacher such interest in the "Lightning Group" claims as was within his power to sublease to the D.A.C. Uranium Co., who by virtue of such sublease is now in rightful possession of the eight mining claims known as the "Lightning Group," and so long as mining operations are conducted thereon in good faith for six months of each year, it is incumbent upon the defendants Benton and Brady to respect this right of possession and to refrain from interfering therewith.

See also Rees v. Emmons Coal Mining Co., 88 W. Va. 4, 106 S.E. 247 (1921); cf. Miller v. Fredeking, 101 W. Va. 643, 133 S.E. 375 (1926); 11B Michie's Jurisprudence Landlord Tenant § 57 (1978). The general rule elsewhere is that unless there is some statutory prohibition or an express provision in the lease to the contrary, a lease on real property, other than a tenancy at will, is assignable.Crump v. Tolbert, 210 Ark. 920, 198 S.W.2d 518 (1946); Kassan v. Stout, 9 Cal.3d 39, 106 Cal.Rptr. 783, 507 P.2d 87 (1973); Ochsner v. Langendorf, 115 Colo. 453, 175 P.2d 392 (1946); Rauch v. Circle Theater, 176 Ind. App. 130, 374 N.E.2d 546 (1978); Valley Oil Co. v. Barberian, 344 Mass. 759, 183 N.E.2d 109 (1962); Todd v. Board of Educational Lands and Funds of Neb., 154 Neb. 606, 48 N.W.2d 706 (1951); Kruger v. Page Management Co., Inc., 105 Misc.2d 14, 432 N.Y.S.2d 295 (1980); Gripentrog v. City of Wahpeton, 126 N.W.2d 230 (N.D. 1964); Powerine Co. v. Russell's, Inc., 103 Utah 441, 135 P.2d 906 (1943); 49 Am.Jur.2d Landlord and Tenant § 398 (1970); 51C C.J.S. Landlord and Tenant § 31 (1968). In the present case, we note that the lease was assignable.

To be available as a defense it must be raised in the pleadings, and cannot be urged for the first time in this court on writ of error. Rivera v. Queree, 145 Colo. 146, 358 P.2d 40; Ochsner v. Langendorf, 115 Colo. 453, 175 P.2d 392. MR. JUSTICE MOORE delivered the opinion of the Court.

* * *." This rule has been repeatedly applied and enforced in the following recent decisions: Markley v. Hilkey Bros., 113 Colo. 562, 160 P.2d 394; Buss v. McKee, 115 Colo. 159, 170 P.2d 268; Seeger v. Puckett, 115 Colo. 185, 171 P.2d 415; Carson v. McNeill, 114 Colo. 78, 162 P.2d 226; Ochaner v. Langendorf, 115 Colo. 453, 175 P.2d 392. In addition to the foregoing and as further reason why the plea of res judicata is not available to the bank herein, the judgment roll in No. 3527, relied upon here, was neither introduced in evidence on the trial, nor included in the abstract; nor was any supplemental abstract containing said judgment roll filed herein.

A landlord who accepts payment of rent at the expiration of a lease without renouncing the prior agreement can be found by operation of law to have agreed to the terms of the original lease. Ochsner v. Langendorf, 115 Colo. 453, 175 P.2d 392 (1946). Bank argues, however, that we should not apply these concepts here because the termination of the tenant's lease by foreclosure pursuant to § 38-39-106 and § 38-39-110, C.R.S. (1982 Repl. Vol. 16A), and the creation of a new landlord make this situation significantly different than a traditional landlord/tenant "holdover."