MALCOLMSON OLD RED SANDSTONE. 345 



high as Orton, where it rests on the gneiss, which has been brec- 

 ciated by the intrusion of quartz-rock. Opposite the termination of 

 these cliffs, at Dipple on the other side of the river (fig. 6), beds of 

 shale, alternating with thin bands of a red sandstone- conglomerate, 

 are exposed in a low bank, at the foot of which the river probably 

 once flowed, but which is now separated from it by some fields*. 

 No rocks are seen on the same side of the river for a considerable 

 distance above Dipple, the country being covered by a great accu- 

 mulation of drift ; but, previously to the excavation of the bed of 

 the river, the great conglomerate must have extended to within a 

 few hundred yards of the shales under which they appear to dip. 

 The shale consists of a few thin strata of a soft unctuous argillaceous 

 schist, containing a good deal of iron and very little lime ; and it 

 has proved injurious to the soil to which it was applied as a manure. 

 A number of calcareous nodules are thinly scattered through it, which 

 exhale a disagreeable smell, and are much withered from long ex- 

 posure. From this cause, and the circimistances that seem to have 

 attended the formation of the deposit, no well-preserved specimens 

 have been obtained from this locality, with the exception of the 

 singular arched bone and other parts of the Coccosteus, and various 

 single scales of a radiated structure f. One of these specimens, 

 belonging to Mr. Martin, has a zoned and radiated structure of 

 great beauty, and so nearly resembles a unique specimen found by 

 Mr. Noble at Clashbinnie, that I have had a drawing made of each 

 (figs. 1, 2, and 3, drawing 3), this being the only instance in which 

 these inferior beds have furnished any fossil similar to those of the 

 upper series. These specimens should be carefully compared with 

 each other, and with the scales of a species of Holoptychus from 

 Burdiehouse, which has the same structure (fig. 2, drawing 23). 

 It is proper, however, to state, that the middle layer of the scales 

 of the Diplopterus, Dipterus, &c., presents the same radiated ap- 

 pearance, and in some individuals the rays are crossed by fine trans- 

 verse bands, giving the scale, under the microscope, the appearance 

 of a most beautiful and regular network. In some of the specimens 

 the characters of the genus Diplopterus and of the Osteolepis Uragus 

 are sufficiently evident. 



A fine section of the superior beds is displayed on the bank of the 

 river where it is crossed by the great North road (Upper beds, fig. 6), 

 and has been several times described. On tracing the fish-beds 



* This inference has been since confirmed by a detailed examination of the 

 hill of Finlay Scat (1123 feet high by trigonometrical measureraent), forming 

 the south side of the vale of Rothes, and on the north part of which the conglo- 

 merate of Scat-craig near Elgin (so rich in the fossils of the middle division) 

 rests. This hill is entirely formed of the great conglomerate which has been 

 traced in various ravines to no great distance from Dipple, under the fish-beds 

 of which it seems to pass. 



t The curious bony ridge on the reverse of many of the scales at Dipple first 

 assured us that the shales and nodules contained remains. It forms a useful 

 practical means of distinguishing dijfferent specimens, and I have detected it in 

 the ichthyolites of Orkney, Cromarty, Lethen, and Tynat. It belongs to the 

 fish (figured in the drawings, plates 1 & 2) which has two opposite anal and 

 dorsal fins, and a close-set row of fine equal comb-like teeth in both jaws. 



