ETHERIDGE LEYOXIAX ROCKS AND FOrSSILS. 



603 



On the latitude of Kentisbmy and Lower Eowley, and between 

 these two locahties in the middle of the lower division of the Ilfra- 

 combe group, we again have clear evidence of contemporaneous ig- 

 neous action, as exhibited in Lower Rowley quarry, where stratified 

 thick-bedded white, grey, pale-brown, and green felstones(?) are 

 worked, and used for road-material : a thickness of from 50 to 70 

 feet is exposed ; but their upper face being covered by fissile slates, 

 and the base not seen, their thickness is unknown. My attention 

 was drawn to this remarkable rock by roadside-heaps, showing its 

 hard porcelain-like character, differiug from the Bittadon poi-phyr^^ 

 or any known rock in Xorth Devon. In Lee Bay a greenstone dyke 

 occurs, striking east, and in a direct line with Kentisbury and Eow- 

 ley : but an intrusive dyke may take any bearing or direction ; 

 and therefore no hypothesis is justifiable to account for metamor- 

 phic action, so far away from what might otherwise cause this 

 change. This Lee dyke and the one at Fremington Pill also, 

 south of Barnstaple, I doubt not belong to the grand system of 

 intrusive greenstones that intersect the slates and granite of Lundy 

 Island, there being no less than 60 dykes, varying from 1 foot to 

 30 feet in width, that traverse that remarkable island from east to 

 west in the space of 2| miles, affecting both granite and slates alike, 

 all of which have been carefully examined and mapped by myself*. 



Bands of limestone in red slates, containing Cyatlioplinllum cces- 

 pitosmn and casts of bivalve shells, succeed those at Higher Kowley, 

 dipping south, and which, with those of Challacombe and Tvrichin, 

 appear to be the highest known calcareous beds in this lower di- 

 vision of the Ilfracombe group. Then set in the Lee and Morte- 

 hoe slates, which are traceable into the beautiful dale and ravine 

 of Arlington, and immediately underlie the high land of Garmond 

 Down, Bratton Down, Span Head, &c., — portions of the upper and 

 persistent zone of red sandstones and grits that stretch from Morte 

 Bay to ^iveliscombe — in other words, the Pickwell Down series, 

 stated by Professor Jukes to be the faulted or repeated series of 

 the Foreland, ten miles to the north. 



The junction of the Lee and Morte-hoe slate series, here, as at all 

 other points along this north line, or outcrop of the red grits and 

 sandstones, is complete, and, as at "Woolacombe, Bittadon, and the 

 Exe YaUey &c., there is no evidence of unconformity, or disturb- 

 ance, either obscuring or destroying local or general continuity ; and 

 the constructed and measured section in Morte Bay, still more 

 to the west, to be yet described, will, I hope, not fail to show this. 

 It is well known that at Bittadon, Smithia Park, and onwards to 

 the east, there arc local exhibitions of igneous rocks, doubtless con- 

 tinuous, if carefully traced ; and notably stands out the Bittadon 

 felstone-porphyry, at or near the junction of the Morte Slates and 

 the base of the red sandstone of Swinham Downf. Eoad-sections to 

 Sherwell Cross and those exposed in the river, to Youlston Old 



* See also Williams (Rev D.), Quart. Journ. Geol. Soc. vol. ii. p. 68. 

 t The Viveham iron mines are a little gouth of this, and were once exten- 

 sively worked. 



