79 



The first genus (Dipterus) has a double dorsal fin, and the other fins 

 are nearly in the same position as in the Esocii. — One of the species 

 (Dipterus macrolepidon) is remarkable for the size of its scales, which 

 sometimes exceed half an inch in diameter. The second genus is 

 nearly allied to Amia and Lepisosteus. The body is covered with 

 hard quadrangular scales, disposed in oblique rows. In all the spe- 

 cies the peculiar formation of the tail, before alluded to, is the same. 



Along with the fish were found the remains of aTestudo, nearly al- 

 lied to Trionyx, and one specimen of a vegetable impression : but not 

 a single fossil shell or zoophyte has yet been discovered in any part 

 of the county. It adds to the interest of this singular assemblage 

 of organic remains, that they all resemble the inhabitants of fresh 

 water. 



§ 5. Secondary deposits on the shores of the Murray Firth. — Several 

 transverse sections through these deposits are described in great de- 

 tail ; and from a comparative view of the phenomena exhibited in a 

 section from the conglomerate mountains in East Ross to the north 

 Sutor of Cromarty, and from thence to Tarbet Ness, it appears that 

 these secondary deposits admit of three natural divisions, like those 

 described in Caithness. The conglomerates in both counties are the 

 same. The formations in the lower region of East Ross contain sub- 

 ordinate beds of calcareo-bituminous schist ; and though fossils are 

 much more rare than in Caithness, yet a few examples of fish-scales, 

 and a fragment of a Testudo resembling a Trionyx, have been found 

 between the north Sutor and Tarbet Ness. — Lastly, the highest beds 

 of the whole series near Tarbet Ness, may be compared with the 

 newer red-sandstone of the Pentland Firth. 



The transverse sections exhibited near the south shores of the Mur- 

 ray Firth, differ considerably in their details from what has been de- 

 scribed. The bituminous schists seem to be in some measure replaced 

 by beds of concretionary limestone, resembling thecornstone of Here- 

 fordshire : and these beds are surmounted by a great formation of 

 white sandstone, nearly resembling the sandstone associated with the 

 coal measures between the old and new-red-conglomerates in the Isle 

 of Arran. 



§ 6. Red-sandstone and conglomerate series on the N.W. coast of Su- 

 therland and Ross-shire. — These extend almost without interruption 

 from Cape Wrath to Applecross ; and the authors (after stating a few 

 facts in addition to the details already given by Dr. MacCulloch) as- 

 sert that, through the intervention of the patches of conglomerate on 

 the north coast of Scotland, they are most intimately connected with 

 the conglomerates which extend from Port Skerry to the Ord of Caith- 

 ness. The two systems appear also to be identical in their general 

 character and relations. There are some difficulties arising out of the 

 peculiar modifications of the quartz-rock, which sometimes cannot be 

 distinguished, mineralogically, from that of the unconformable red- 

 sandstone and conglomerate series. The authors have, however, no 

 hesitation in classing the great red-sandstone series, which extends 

 from Applecross to Cape Wrath, with the older portions of the se- 

 condary deposits of Caithness and Sutherland. 



