108 MR. GARDINER AND PROF. REYNOLDS ON THE [Jmie 1914, 



ends, which might come under Amphibrachiwn, and two conical forms which 

 might be Dictyomitra or Stichocapsa. But in all there are only bare outlines 

 remaining, partitions and meshwork have all disappeared. One object in the 

 slide from the spot marked 103 is a fragment of a fair-sized sponge-spicule.' 



It will be convenient here to allude to the fact that similar 

 radiolaria were found in banded chert, at a point marked 62 on 

 our map (PI. XVII), two-thirds of a mile farther Avest. Higher 

 up the more northerly of the two streams, other exposures of chert 

 occur, at first vertical, but as one passes farther west dipping 

 southwards- — at one point at an angle of 60°. 



After one has crossed the col at the head of the vallej', further 

 chert-bands, dipping in a general southerly direction, are seen. 

 The fine tuffs associated with the limestone-breccias (see below), 

 a third of a mile west-south-west of Red Island, are vertical or dip 

 southwards at a very high angle. 



Thus, while in the eastern part of the Lough Nafooey area the 

 tuffs, cherts, and other sediments dip northwards and overlie the 

 spilites, farther west they dip southwards, that is below the spilites, 

 an intermediate area occurring where these rocks are vertical. 

 These facts seem most readily explicable on the supposition that 

 the western strata with the southerly dip are really inverted. If 

 this be the case, the cherts and limestone-breccias belong to the 

 upper part of the spilitic series, and the Lough Nafooey area is in 

 accord with the Kilbride area, in which the fossiliferous cherts and 

 shales occur high in the spilites — as also with the Glensaul and 

 Tourmakeady areas, in which the limestone-breccias belong to the 

 upper part of the Arenig development. 



(3) The Calcareous Rocks. 



The districts of Tourmakeady and Glensaul are characterized 

 by a peculiar type of calcareous deposit — limestone-breccia ; and 

 Mr. Maufe and Mr. Carruthers have described a similar rock from 

 the Upper Arenig of the Leenane district. No such rock was seen in 

 the Kilbride area, but in the Lough Nafooey area it is again found 

 at two localities, one a third of a mile south-west of Red Island, the 

 other at Curraghrevagh hamlet. The characters of this deposit may 

 best be studied at the former locality. As in the Tourmakeady and 

 Glensaul areas, the matrix consists of coarse quartzose grit or some- 

 times tuff, enclosing fragments of chert and f elsite and pieces of grey, 

 red, and white limestone, generally of a compact horny texture, and of 

 all sizes up to the length of 14 inches. Pieces of crinoid-stem are 

 fairly common in the limestone, and a fragment of an Illcrnus was 

 found ; in the matrix only a few unrecognizable fragments of 

 trilobites and brachiopods were met with, together with a Cvstidean 

 plate, concerning which Dr. Cowper Reed writes that it suggests 

 Mchinoencrinus senchenbergi H. von Meyer, a Lower Ordovician 

 form. Near Curraghrevagh, limestone-breccia is seen in and near 

 the stream at the north-eastern end of the hamlet, and it has 

 been worked in one field immediately north, and in another about 



