THE HIGHLAND BORDER ROCKS OF THE ABERFOYLE DISTRICT. 
187 
LIST OF FOSSILS FROM THE CHERTY BEDS. 
I. Radiolaria. 
II. Graptolitoidea. 
Forms belonging to the family 
of Diplograptidse — Trigono- 
graptus or Cryptograptus. 
A form of the family Retiolitidse. 
III. Brachiopoda. 
Obolus, Eichwald — species inde- 
terminate. 
Lingulella aff. ferruginea , Salter. 
,, aff. nicholsoni, Callo- 
way. 
Acrothele • ( Obolella ) maculata, 
Salter. 
,, ( Redlichella ) granu- 
lata , Linn. 
Acrothele aff. coriaceae, Linn. 
Acrotreta nicholsoni, Day. 
,, socialis, von Seebach. 
,, aff. sabrinse, Calloway. 
Siphonotreta aff. micula, M‘Coy. 
,, aff. scotica, Day. 
? Schizambon, Walcott. 
IY. Phyllocarida ( Leptostraca ). 
Modiolocaris dakynsi, Peach, nov. 
Other forms allied to Lingulo- 
caris, Salter, and to Pelto- 
caris , Salter. 
V. Incertse sedis. 
Various remains of Arthropods, 
etc. 
I. RADIOLARIA. 
Remains of Radiolaria occur in profusion in the purer cherts and to a less 
extent in the cherty shales, not only at the fossil localities indicated on the map, 
but also elsewhere. They are seen to be abundant on a microscopic examination of 
thin sections of the rock, and can be detected even in hand specimens by means of a 
strong lens. Usually they appear as mere casts, round or oval in form ; frequently 
they show a lattice-like pattern, or look like small circles with spines radiating from 
the centre like the spokes of a wheel (Plate I, figs. 5,7, and ll). 
II. GRAPTOLITOIDEA. 
Graptolites are extremely scarce. A few specimens have been obtained from the 
cherty shales at the Bofrishlie Burn locality, between Arndrum and Dungarrow. 
The first specimen identified as a graptolite was detected by Dr Ami of Canada in 
the collection of fossils from the Aberfoyle district exhibited by Dr Jehu at the 
Dundee Meeting of the British Association in 1912. In a letter to Dr Horne, 
Dr Ami stated that he had recognised an obscurely preserved graptolite resembling 
Retiolites ensiformis Hall, a type characteristic of the Sillery Sandstones of the 
Quebec Group (Upper Cambrian). This specimen was examined subsequently by 
Miss Gertrude Elles, Cambridge, who kindly supplied the following figure and 
description : — 
“ The specimen appears to me to show traces of thecse, with a fairly well- 
developed reticula and clathria. It would appear to belong to the Retiolitidae. The 
