Such peculiarities agree with the characters of the crustaceans met with in the Cambrian strata of Wales; and Dr. Torell has recently found in Sweden the Paradoxides Hicksii, a well-known Lower Cambrian fossil.

In the past we have the evidence of the fossil Paradoxides that creatures of this kind may at least attain a length of six feet, and, considering their intense pugnacity, a crab of such dimensions would be as formidable a creature as one could well imagine.

Hicks and Salter, to whose exertions we owe almost all our knowledge of the fossils, have pointed out that the most characteristic genera found in them are quite unknown in the Lingula Flags, while they possess many of the strictly Lower Cambrian genera, such as Microdiscus and Paradoxides. David's. The beds are well exhibited in the neighbourhood of St.

FOREIGN. Ungulite or Obolus grit of Russia. BRITISH. Tremadoc slates. FOREIGN. "Primordial" zone of Bohemia in part, with trilobites of the genera Paradoxides, etc. BRITISH. Menevian beds of Wales, with Paradoxides Davidis, etc. FOREIGN. Lower portion of Barrande's "Primordial" zone in Bohemia. BRITISH. Fundamental gneiss of the Hebrides? FOREIGN. Labradorite series north of the river St.

In Merionethshire, according to Professor Ramsay, the Lingula Flags attain their greatest development; in Carnarvonshire they thin out so as to have lost two- thirds of their thickness in eleven miles, while in Anglesea and on the Menai Straits both they and the Tremadoc beds are entirely absent, and the Lower Silurian rests directly on Lower Cambrian strata. Paradoxides Davidis, Salter.

The Middle Cambrian is marked by the genus Paradoxides, and the Upper Cambrian by the genus Olenus. Some of the Cambrian trilobites were giants, measuring as much as two feet long, while others were the smallest of their kind, a fraction of an inch in length.

A new genus of trilobite called Plutonia Sedgwickii, not yet figured and described, has been met with in the Harlech grits. It is comparable in size to the large Paradoxides Davidis before mentioned, has well-developed eyes, and is covered all over with tubercles.

Agnostus Rex, Barr. Sao hirsuta, Barrande, in its various stages of growth. The small lines beneath indicate the true size. In the primordial zone C, he discovered trilobites of the genera Paradoxides, Conocoryphe, Ellipsocephalus, Sao, Arionellus, Hydrocephalus, and Agnostus.

The third fauna agrees with the Upper Silurian of the same author. These numbers have since been almost doubled by subsequent investigations in the same country. Fossils of the lowest Fossiliferous Beds in Bohemia, or "Primordial Zone" of Barrande. Paradoxides Bohemicus, Barr. Conocoryphe striata. Syn. Conocephalus striatus, Emmrich. One-half natural size. Agnostus integer, Beyrich.

These schists contain trilobites belonging to the genera Paradoxides, Olenus, Agnostus, and others, some of which present rudimentary forms, like the genus last mentioned, without eyes, and with the body segments scarcely developed, and others, again, have the number of segments excessively multiplied, as in Paradoxides.