384 Correspondence — Mr. D. Mackintosh. 



are indeed some masses of drift-gravel and cbalk wasli at and near 

 the top of the Boulder-clay, which seem to have been formed on the 

 spot; but these contain no shells. 3. Fragments of Secondary- 

 deposits occur in the clay in the same way as these shelly patches. 

 See Prof. Phillips's description of a large mass of Lias with fossils 

 (which did not live where they occur) on the beach at Bridlington ; 

 (Geol. of Yorkshire, 3rd ed. p. 85) ; Mr. Mortimer's, of a mass of 

 chalk with lines of black flint, at Easington (Proc. Yorkshire Geol. 

 Soc. 1881, p. 375) ; and my own, of Neocomians at Flambro (Proc. 

 Yorks. Geol. Soc. 1880, p. 245), and at Dimlington (Geol. Mag. 

 Dec. 1881, p. 541). 4. The whole aspect of the clay shows that the 

 drift has not been from the land. The proportion of chalk in it is 

 not great, the flints are nearly always black or red, and not grey 

 like those in the Yorkshire Chalk, strange igneous rocks are plenti- 

 ful, and Lias and Neocomian remains are relatively far too abundant 

 to have been carried over from the opposite side of the Wolds. 



The evidence is also against the view that the confusion in the 

 beds may be attributed to the passage of later ice ; for though there 

 are signs that this has had its local effect, yet as the Basement Clay 

 retains its peculiar features where beds of sand, gravel, or laminated 

 clay come between it and the overlying Boulder-clay, its character 

 cannot have been greatly altered. 



The sands and gravels connected with the Purple Clay, to which 

 Mr. Wood at first referred these shells, have evidently in most cases 

 been deposited where they now lie, and formed from the same 

 materials as the clay. But if Mr. Wood has not seen the shelly beds 

 I described, and has had his impression that they are in place con- 

 firmed by my paper, I fear my descriptions must be misleading, and 

 I beg leave now to correct them on this point. 



It must always be remembered that at Dimlington there is a great 

 space between the Shelly Boulder-clay and the Chalk which is as yet 

 entirely unaccounted for, and it is very probable that traces of un- 

 disturbed shell-beds may some time be found lower down in the 

 section. G. W. Lamplugh. 



Bridlington Quay. 



HIGH-LEVEL DRIFTS IJST NOETH AMERICA. 

 SiK, — In answer to Mr. Lesley's important letter on high-level 

 drifts, I would beg to state that those I discovered on Minera moun- 

 tain, North Wales, contained marine shells up to about 1280 feet 

 above the present sea-level, while shells had previously been found 

 on Moel Tryfan up to 1370 feet. I have not yet heard of shell- 

 bearing sand and gravel in North America at a higher level than 

 700 feet. Is this their extreme altitude ? 



D. Mackintosh. 



Ekatum. — On page 320, in the fourth column, the first three lines 

 should not read as printed with the brace, but as follows : — 

 Overlying Zone of Ammonites planorbis. 



( Kossener Schichten and Dachstein Series. 

 ( ' Hauptdolomit ' of Tyrol, and ' Plattenkalk.' 



