Mr. Winch on the Eastern Part of Yorkshire. 557 
enormous casts of ammonites, similar to those found in the west of 
England, occur in abundance. 
Pinna marina — in sandstone, Troutsdale. 
Trigonia clavellata — Parkinson, vol. 3, p. 12, f. 3, limestone, 
Pickering. 
Nautilus nobilis — Malton. 
Cardium resembling C. edule — Malton. 
Ostrea edulis? — Malton and Pickering. 
O. diluviana — Park. vol. 3. pi. 15. fig. 1. on the sands. 
Solen ensis — on the Sands. 
Bivalve, Park. vol. 3. p. 13, fig. 4. on the sands. 
Terebratula coarctata ? — Park. vol. 3, vol. p. 16, fig. 5. — in 
sandstone at Malton. 
Mytilus edulis? — Troutsdale in sandstone, and Malton in lime- 
stone. 
A small rivulet called Peacham beck, brings down a magnetic 
iron-sand, most probably Iserine. 
A short distance below the town of Yarm, a basaltic dyke crosses 
the river Tees, in an east-south-east direction ; and basaltic emi- 
nences may be traced in the same line by Stainton, Newton Danby, 
Derwent head ; and terminate at Blea hill, in Harwood dale, seven 
or eight miles north-west from the coast. But whether these masses 
have any connection with the dyke it is impossible to ascertain. 
That it is really a dyke where it crosses the river Tees appears 
very evident ; but in the moorlands I suspect the low eminences of 
basalt are similar to those at Shewingshield in Northumberland. 
It may be here observed, that the basaltic dykes in the Newcastle 
coalfield are known to terminate abruptly ; for instance, those at 
Coley hill and Walbottle Dean, noticed in my former paper, are 
not found in the mines situated a short distance to the east of those 
