Vol. 59.] SOUTH DEVON AND THE MIDLANDS. 321 



Almost all these species are stated to occur at the quarries of May. 

 This fact is of some interest, for the Gres de May itself, which 

 is not found farther west than the department of the Manche, appears 

 to be subject to local variation in its palseontological facies. There 

 are also allied grits, having a somewhat different fauna, in the 

 department of Ille-et Yilaine, etc. ; but if any one locality be 

 taken, the greater number of correspondences will be found in the 

 Ordovician of May, 



The lithological evidence is equally remarkable. It was noticed 

 by J. W. Salter, 1 Mr. Ussher, 2 and A. Wyatt Edgell. 3 



On the occasion of two visits to the district, I was much im- 

 pressed by the apparent lithological identity between the Gres de 

 May and a very large proportion of the JBunter pebbles. The 

 resemblance extends to peculiar and strongly -marked features, 

 such as the irregular way in which the quartzite is frequently 

 stained with red patches or blotches, and it is worthy of note that 

 these resemblances are especially conspicuous at the quarries of 

 May. At Jurques and Montpincent the staining is usually absent. 

 At May I noticed the close similarity between the softer parts of 

 the May sandstone and certain soft reddish pebbles in the Drift 

 which had puzzled me as to their origin. 



I found a section of the Gres feldspathique by a roadside near 

 the village of May, and was at once struck by its strong resemblance 

 to the quartz-felspar grit of the Bunter and of our river-gravels. 

 The rock itself in this small section was found to be variable, both 

 in the size and proportion of the felspar-grains, which is the case 

 also with the Bunter pebbles ; so that, in comparing specimens 

 from one locality with another, only a general resemblance in type 

 would be expected. 



I am aware that the argument from lithological similarity should 

 not be pushed too far ; but, in order that we may know all that can 

 be known regarding these rocks, I submitted certain types to 

 Prof. Bonney, and he has kindly sent me the results of his exami- 

 nation of them. On No. 1 (a specimen of the May sandstone, or 

 quartzite, from the quarry at Feuguerolles) Prof. Bonney remarks : — 



'1. (May) Hand-specimen.— Very like the liver-coloured quartzite found 

 in pebbles both in the Midlands and at Budleigh Salterton. 



' Microscopic characters. — Grains fairly rounded, distinctly outlined by 

 a deposit of ferrite. There may possibly be one or two minute grains of tourma- 

 line. In the Midland specimens the gvains are much more angular, and much 

 less distinctly outlined, but with a general appearance as if they themselves 

 were coloured. The latter also contain granules of zircon, rutile or sphene 

 (perhaps both;, and probably tourmaline. But as the localities are far away, 

 the differences may not be worth much. 



'2. Gres feldspathique (near May). Hand-specimen. — Very like 

 Torridon Sandstone and the quartz-felspar grit of the Bunter Pebble-bed, 



1 Quart. Journ. Geol. Soc. vol. xx (1864) p. 287. 



2 Ibid. vol. xsxv (1879) p. 245. 



3 Ibid. vol. xxx (1874) p. 45. 



