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imperfectly the nature of the trench and the location of the rock summit in its buried floor, he is liable to mistake this obscured rock summit for a true col. It is, in fact, not a col at all in any proper sense. It never has been a watershed, and has never performed the functions or sustained the relations of a true col. As there is frequent occasion to refer to this phenomenon in the discussion of certain regions of reversed drainage along the border of the ancient glacial formations, I propose for it the distinctive name pseudo-col. The nature of the phenomenon has been more or less distinctly recognized by many geologists. The purpose of this note is merely to bring it forth into more definite recognition and to supply it with a convenient name which may be used in lieu of the cumbersome periphrastic phraseology now required.

In a paper entitled "On the geological structure of the Housatonic valley lying east of Mt. Washington" (Journal of Geology, Vol. I, No. 8), I proposed the term (p. 791) weather-board structure as an equivalent of Suess's term Schuppenstruktur to describe a structure caused by a series of small compressed overfolds finding relief through dislocation, and resulting in the production of a parallel series of overlapping plates. Mr. Bernard Hobson, of Manchester, England, has suggested to me that the term imbricate structure would be better because of its Latin derivation and its use in botanical literature. The two terms are practically identical as regards the idea conveyed, and though the term first suggested would perhaps give a better mental picture to many minds, Mr. Hobson's term would be more readily understood abroad, and has the added advantage of being the English equivalent of Margerie's structure imbrique. I should therefore be glad to see imbricate structure adopted rather than the term which I at first suggested.