THE PLIOCENE BEDS OE ST. ERTH. 



203 



One observed dip gave about S^° to 4° to J^.N.W. ; but the true 

 dip is probably 5°. 



Mr, Wood states, on the authority of Mr. Cornish, that the clay 

 occurs as a lenticular patch in the midst of the sand ; but though the 

 section was much obscured when our examination was made, all the 

 appearances then presented led to the conclusion that the bedding 

 was quite regular (see fig. 2). 



Fig. 2. — Section in West Corner of Sand-int, St. Erth. 



At a slightly less elevation to the N.N.E. a thick bed of " Growder " 

 (probably No. 7) occurs, and about three hundred yards to the west, 

 in a deep quarry beside the road leading from the St. Erth Post- 

 Office to Hayle, and excavated in an elvan dyke, the " Growder " 

 is seen resting directly upon an irregular surface of the felsite, 

 fragments of which, in a greatly decomposed state, are imbedded in 

 the sand. The same " Growder " is to be seen along the roadside 

 at various points nearly as far as the village of St. Erth. 



A short distance along the road in the opposite direction, in the 

 corner of afield called " Moor Meadow," a small pond was excavated, 

 as we are informed, in the Blue Clay, but no fossils were observed. 

 At the present time it is filled in by surface mould, but some traces 

 of clay could be seen. 



In a lane to the south of St. Erth, a roadside-cutting is said to 

 have exposed the Blue Clay, but only obscure traces of it can now 

 be seen. 



The extent of the lines of outcrop is not traceable on account of 

 the covering layer of " Head," which is in many places of con- 

 siderable thickness, and the cuttings necessary to confirm the state- 

 ments made to us could not be made, owing to the short time avail- 

 able and to the inclement weather ; for the same reason, dips and 

 levels could not be taken. The area embraced by these alleged 

 exposures is atout one hundred and twenty acres. 



The lithology of these beds cannot be treated exhaustively in this 

 communication, owing to the difficulty of obtaining clean and un- 

 mixed specimens, consequent upon the falling in of the side of the 

 pit. 



The sands are of well-rounded quartzose grains, primaril)'- derived 

 from some Plutonic rocks. Black grains occur, which are probably 

 hornblende. 



The difference in colour of the two clays is, no doubt, attributable 



