Geological Society of London. 189 



basic rocks. These structures continue altogether independent of 

 the varying distribution of the gabbros, and are seen even where 

 the granophyre runs along the side of the agglomerate. Similar 

 structures are of common occurrence along the margins of the 

 granophyre-bosses and sills of the Inner Hebrides, being found, 

 not only next the gabbro, but next the Jurassic sandstones and 

 shales. They are familiar phenomena of contact in all parts of the 

 world, and are sufficient of themselves to show that the granophyre 

 of Skye must be later than the gabbro. 



The author then describes three conspicuous dykes, from eight to 

 ten feet broad, which can be seen proceeding from the main body 

 of granophyre and cutting across the banded gabbros. One of these 

 is traceable for more than 800 feet in a nearly straight line. The 

 material composing these dykes is identical with that constituting 

 the marginal portion of the granophy re-mass. It presents the most 

 exquisite flow-structure, with abundant rows of spherulites. The 

 author exhibited a photograph of one of the dykes ascending vertically 

 through the gabbros. Numerous dykes and veins of the same 

 material, not visibly connected with the main granophyre-mass, 

 traverse the gabbros of the ridge of which Druim an Eidhne forms 

 a part. Some of these are described in the paper, and it is shown 

 that the flow-structure follows the irregularities of the gabbi'o- 

 walls and sweeps round enclosed blocks of altered gabbro. The 

 "inclusions" described by Prof. Judd are portions of these dykes 

 and veins. There is not, so far as the author could discover, a 

 single granite-block enclosed in the gabbro anywhere to be seen 

 at this locality. He therefore claims not only that his original 

 description of the relations of the rocks was perfectly correct, 

 but that the evidence brought forward to contradict it by Prof. 

 Judd furnishes the most crushing testimony in its favour. 



2. " Note on the Genus Naiadites, as occurring in the Coal 

 Formation of Nova Scotia." By Sir J. William Dawson, K.C.M.G., 

 LL.D., F.K.S., F.G.S. With an Appendix by Dr. Wheelton Hind, 

 B.S., F.R.C.S., F.G.S. 



The specimens referred to in the paper occur most abundantly in 

 calcareo-bituminous shales along the coast, at the South Joggins, 

 and were described by the author in " Acadian Geology," in 1860. 

 A collection of them has been submitted to Dr. Wheelton Hind. 

 In Q.J.G.S. vol. xix. Mr. Salter referred the shells described as 

 Naiadites to his new genera Anthracoptera and Anthracomya. In 

 correspondence with Mr. Salter, the author held that the shells 

 were probably fresh-water, and objected to the name Anthracomya 

 as expressing an incorrect view of the affinity of the shells ; he 

 also stated several reasons in support of his ojjinions. The author 

 continued to use the name Naiadites, but does not object to the 

 division of the species into two genera, for one of which Salter's 

 name Anthracoptei-a should be retained. Additional reasons are 

 given for the fresh-water origin of these shells, and the author 

 expresses his gratification that their affinities have been so ably 

 illustrated by Dr. Hind. 



