84 



Mr. De la Beciie on the Geology of Part of France. 



size from that of a pea to three or four inches in diameter, and agglutinated 

 by a hard red argillo-siliceous cement, in which are small crystals of felspar. 

 I did not perceive that it was stratified : it appears to rest upon nearly vertical 

 strata of argillaceous slate and grauwacke. 



A similar rock occurs at St. Laurent de Condel on the same road, under 

 oolite, and is exposed to view in one part of the high ground between Va- 

 lognes and St. Vaast, though generally concealed by the gravel beds. This 

 porphyritic conglomerate bears a striking resemblance to that which occurs 

 under the same circumstances in the neighbourhood of Exeter. 



Coal Measures. 



These strata are found at Litry, E.S.E. of Bayeux*, extending about 1700 

 yards from east to west, and 850 yards from north to south ; their direction is 

 east and west, and their dip 22° to the north. Some of the coal beds are of 

 tolerable thickness ; they vary much in quality, and are not in general very 

 good. They rest upon argillaceous slate. 



Old Red Sandstone. 



I am inclined to refer to this formation the compact sandstone found at 

 May, between Caen and St. Laurent de Condel. It rests upon what is usu- 

 ally termed transition limestone, and with it is exposed to view by a large 

 denudation in the oolite formation. This sandstone is either white, red, or 

 blueish ; its beds vary in thickness, and are sometimes micaceous ; their dip 

 is about 45° to the north ; they are extensively wrought for paving and 

 flag stones. 



The sandstone which rests on quartz rock between Cintaux and Langan- 

 nerie, on the road from Caen to Falaise, may be a continuation of the 

 May beds. 



Compact Limestone with Slate. 



A small portion of these substances occurs under the sandstone near May ; 

 the limestone is very compact, and in beds two or three feet thick, between 

 which are thin beds of slate. 1 did not observe any organic remains in it ; 



* Sec JoBinal des Mines, Tom, xii. page 346. 



