-30 Revieics — Geological Surveij — 



The Dartmouth Slates within the area are by no means an 

 interesting formation, traces of limestone being very i-are, so that 

 there is no reason to wonder at the lack of fossil evidence. Igneous 

 rocks are " very occasionally " met with, some of which may be in. 

 part contemporaneous. The absence of organisms seems to be the 

 chief distinguishing feature of these basal rocks, so that where 

 traces of crinoids, brachiopods, or corals occur the presumption is 

 against such strata belonging to the Dartmouth Slates. 



The Meadfoot group is far more interesting, and, as its members 

 occupy the principal portion of the Devonian area between the 

 suggested anticline and the Metamorphic boundary, the entire series 

 may be taken as the typical representative of the Lower Devonian 

 in the Kingsbridge-Salcombe peninsula. The following are the 

 divisions adopted, as we have seen, by the author, in ascending 

 order, viz. : the Kingmore Type, the Torcross Type, the Beeson 

 Grits, and the Tinsey Head Slate Series. Judging from the Director's 

 preface, it would appear that when the new maps (sheets 355 and 356) 

 were published in 1898 Mr. Ussher had not then established the 

 fact that the Devonian rocks on the south of the Dartmouth Slates 

 " are parts of the Meadfoot series, and correspond to the types 

 met with in that series in the Looe, Plymouth, and Long Sands 

 (south of Brixham) coast series " (p. 56). 



Dealing briefly with the four above-named series in ascending 

 order, we find that there is a considerable amount of brown-coloured 

 fossil iferous material in beds of the Ringmore type, though actual 

 limestone is seldom discernible in tlie inland localities. Crinoidal lime- 

 stone films and lenticles, often red-stained, are met with in certain 

 localities, and well-known Lower Devonian genera may be recognized 

 with more or less certainty in these crushed calcareous films, though 

 too often flattened out beyond specific recognition. On the whole, 

 these beds must have originally included a fair amount of organic 

 remains, and at Eiugmore itself, in about tw^o feet of glossy and 

 variegated shales, were found flattened impressions resembling 

 Simifera primceva, Streplorhynchus gigas, and Zaj)hrentis ; also the 

 eye of a large trilobite, possibly Fhacops latifrons. This seems 

 to be about all that can be done in the way of palaeontology, 

 though doubtless the beds have been subjected to careful search 

 for fossils. 



The rocks of the Torcross type are chiefly remarkable for 

 numerous thin bands of igneous rock, generally much decomposed, 

 associated with the slates ; in some cases these igneous rocks may 

 be contemporaneous, though their appearance on the map is more 

 suggestive of dykes, especially the long one at the Torcross end. 

 Certain developments of grit, south of beds of the Torcross type, have 

 been termed Beeson Grits, and these are shown on the map by 

 a deeper colour. Amongst the alternative hypotheses, presently 

 to be considered, is the possibility that these Beeson Grits constitute 

 an anticline, so that the Torcross Slates on the north are carried 

 over on the south of these grits. It is not easy to perceive which 

 hypothesis most commends itself to the author, but on the supposition 



