vill INTRODUCTION. 
Pendock, not only seized every opportunity of rescuing 
isolated discoveries from destruction and oblivion, but also, 
by his numerous writings, instigated others to pursue the 
same course. The late Dr. D. M. McCullough, of Aber- 
gavenny, obtained a large series of Pteraspidian shields 
from that neighbourhood, presenting all the finer examples 
to the British Museum; and Monmouthshire was also 
systematically explored by the late Mr. J. E. Lee, F.GS,, 
who likewise added all his discoveries to the National 
Collection. 
The Upper Old Red Sandstone of Shropshire does not 
yield many fossils, but a species of Lothriolepis was obtained 
from these beds in 1862 by Messrs. Baxter and Weaver 
Jones ; and these specimens, with the scales and teeth of an 
undescribed Rhizodont ganoid from the same formation, 
are now preserved in the British Museum. 
The fish-bearing character of the Lower Old Red Sand- 
stone of the Scottish Highlands seems to have been first 
discovered by the late Hugh Miller, of Cromarty, and 
Robert Dick, of Thurso, whose combined collections are 
now, for the most part, preserved in the Museum of Science 
and Art, Edinburgh. The late Lady Gordon Cumming 
made extensive excavations at Lethen Bar, Nairnshire, 
providing many specimens for description by Agassiz, and 
forming the fine collection at present in the Forres Museum. 
An early worker in the flagstones of Orkney was Dr. T. S. 
Traill, whose collection furnished many types of species 
described by Agassiz, and was sold on the founder’s death 
to various collectors; several of the missing types have 
been recognised by the authors of the present work 
among Orkney fossils that have finally reached the British 
Museum, but many important specimens still remain to 
be re-discovered. About twenty years ago the late 
Mr. Charles W. Peach obtained a large series of specimens 
from the flagstones of Wick and John o’ Groats, at present 
forming part of the collections in the British Museum, the 
