1873.] BEYCE — JTTEASSIC EOCXS OF SICYE AND EAASAY. 321 



of the fossils now described, to give a little more precision to the 

 conclusions which he and Dr. "Wright have arrived at in regard to 

 the age of the beds, by simply noting that the Broadford strata 

 represent the main mass of the Lower Lias, and contain such Am- 

 monites as characterize the zone of Ammonites Bucldandi — the 

 coralliferous beds at Lussay being on that of Ammonites angulatus, 

 the lower portion of the Lower Lias. The authors are undoubtedly 

 correct in assigning the Pabba shales to tbe horizon of Ammonites 

 Jamesoni — that is, the lower portion of the Middle Lias. Scalpa was 

 not examined ; and no additional evidence can be brought to bear 

 on the conclusion of the paper (founded on three fossils only, of which 

 not one was an Ammonite), that these beds are the equivalents of the 

 Marlstone and represent the Ammonites-margaritatus and Ammo- 

 nites-spinatus beds of the Middle Lias. Following the beds in their 

 further development northwards, I found the portions of the Lias 

 formation, higher in the series, fully represented and distinctly 

 characterized by the fossils peculiar to the beds in other districts. 

 This will be best shown by a few detailed sections along the line on 

 which the beds successively rise, beginning with those at Sligachan, 

 the southern limit of the area embraced in the present paper. 



Sections of the Beds. — The calcareous strata already referred to 

 as emerging at Sconser are those of the Lower Lias. They occupy 

 the south-east shore of the loch from the sea-line to the height of 

 about 500 feet, where they rise against the syenite of Glamaig. 

 The upper beds, towards the road and sea-level, dip at an angle of 

 about 40°, the lower beds, next the syenite, at 70°, the higher 

 inclination being plainly due to the proximity of the erupted rock. 

 In the northern part of the area the dip is N.W. ; but southwards, 

 as the overlying trap is approached, it is more towards the "W. The 

 ground is so tossed and encumbered with detritus, that a true sec- 

 tion of the beds cannot be obtained. It can only be stated in a 

 general way that the lower beds consist of altered shales, coarse 

 sandstones, and conglomerates, and the upper of indurated dark and 

 grey limestones and dark-coloured shales. The following are the 

 fossils contained in these upper beds : — Gryphcea arcuata, Belem- 

 nites infundibulum, Bhynchonella ammonitica, Pecten textorius, Lima 

 pectinoides, Avicula novemcostce. These seem to show, by com- 

 parison with the Broadford and Hallaig beds, that we are here 

 on the horizon of Ammonites Bucldandi. Calculating from the 

 distance along the outcrop and the average dip, the thickness of 

 the beds may be safely reckoned at 800 feet, which is very much 

 greater than that of the Lower Lias, or indeed any member of 

 the series within the whole of this northern area. There being so 

 little breadth of ground intervening between the base of Ben Gla- 

 maig and the sea, the Middle and Upper Lias could not be expected 

 to come on here ; but both probably exist below the waters of the 

 loch ; and it is to their erosion that reference has been already made. 

 The beds referred to in the same passage as appearing on the "W. 

 shore of the loch at a low level, are a whitish and a dark-coloured 

 sandstone, whose range has been already traced, but whose true 



