In the GeologicalMagazine for September, 1868, I described a section of Drift deposits which, had been exposed in the cutting of the ‘Kilmarnock and Crofhead Extension Railway.’ If the reader refers to that paper he will fine it stated that the Lower Boulder-clay of the locality in question contains certain intercalated beds of clay, sand, and gravel which, have yielded Bos primigenius. Quite recently the remains of the horse and the great Irish deer have been met with in the same deposits. In the present paper I do not mean to say more about the character of the stony clay which overlies the beds with mammalian remains. There can be no doubt whatever that it is truly Boulder-clay. But as I understand that several members of the Glasgow Geological Society have since visited the section, and, while agreeing with me as to the glacial origin of the overlying Till, have yet expressed an opinion that this bed is not in its natural position, but has slipped down upon the stratified deposits from the adjacent hill-slope, it may be well to point out how all the facts are against such a supposition.