SUMMARY OF THE CONTENTS OF THE CATALOGUE, 
BY PROFESSOR MORRIS. 
Cambrian. 
The Lower Cambrian, including the Longmynd and Harlech groups (Sedgwick), is repre- 
sented by but few forms in the collection. These are the Oldhamia, only hitherto found 
in Ireland, some Annelida from the Longmynd, a few Brachiopoda (Lingulella, Obolella), 
and a few Trilobites, which occur low down in the Longmynd group at St David’s Promontory, 
South Wales, as Conocoryphe, Paradoxides, Microdiscus, and the interesting genus Plutonia, 
haying affinities with Paradoxides and Anopolenus, which appears to be restricted to this 
zone, and, next to Paradoxides Davidis is the largest Trilobite found in the British Cam- 
brian rocks. 
The Middle Cambrian comprises the Menevian, Ffestiniog, and Tremadoc groups, 
The fauna of the Menevian, or Lower Lingula flags, is represented by Trilobites of the genera 
Conocoryphe, Agnostus, Olenus, Paradoxides, Microdiscus, Erinnys, Anopolenus, Holocephalina, 
the last three genera being at present characteristic of this zone; Paradoxides and Micro- 
discus here become extinct, while the first three genera range into the zones above: with 
these are found a few Phyllopoda (Primitia, Hymenocaris), some Brachiopoda and Pteropoda, 
(Theca, Stenotheca, Cyrtotheca). The Pteropoda appear to be tolerably abundant in these 
primordial rocks, in which occur also a Cystidean (Protocystites), and some sponges. 
The Ffestiniog group, or Middle and Upper Lingula flags, is chiefly represented by some 
Annelids and Trilobites. The genus Olenus here attains its maximum numerical develop- 
ment, and a species of the allied genus Dikellocephalus also occurs, together with a few 
Brachiopoda belonging to the genera Lingulella, Obolella and Orthis. 
The fossil forms of the Lower and Upper Tremadoc groups chiefly comprise Phyllopoda 
and 'Trilobites: among the latter are the genera, now first noticed, Niobe (intermediate 
to the genera Asaphus and Ogygia), Psilocephalus, a very abundant form, allied to Ilenus, 
Angelina (allied to Olenus), the most abundant of the Tremadoe Trilobites, and species of 
Asaphus, Ogygia, and Cheirurus. There are also some Pteropoda and Heteropoda, as Theca, 
