"Nidulite" is a word in ENGLISH

The earliest period in geological period, extending up to the Lower Silurian. It includes an Azoic age, previous to the …

A genus of trilobites found in the Lower Silurian formation. See Illust. in Append.

A extinct genus of Branchiopoda, very common in Silurian limestones.

A genus of trilobites characteristic of the Silurian age.

Of or pertaining to the lowest subdivision of the rocks of the Silurian or Molluscan age; -- sometimes described as …

A genus of fossil corals, common in the lower Silurian limestones.

An epoch at the close of the Canadian period of the American Lower Silurian system; -- so named from a …

An epoch at the close of the American lower Silurian system. The rocks are well developed near Cincinnati, Ohio. The …

A series of limestone strata found in Ohio and farther west, presenting bluffs along the rivers and valleys, formerly supposed …

A genus of trilobites, of many species, common in the Upper Silurian and Devonian rocks.

A name formerly given to certain Silurian brachiopod shells of the genus Spirifer.

A fossil plant which is found in the lowest beds of the Silurian age.

A genus of extinct Merostomata, found in Silurian rocks. Some of the species are more than three feet long.

A genus of fossil corals abundant in the Silurian and Devonian rocks, having polygonal cells with perforated walls.

One of numerous species of slender and delicate fossils, of the genus Graptolites and allied genera, found in the Silurian …

A genus of Silurian fossil corals; the chain corals. See Chain coral, under Chain.

A fossil coral of the genus Heliolites, having twelve-rayed cells. It is found in the Silurian rocks.

A series of strata in the lower Silurian formations of Great Britain; -- so named from Llandeilo in Southern Wales. …

A subdivision of the British Upper Silurian lying below the Old Red Sandstone; -- so named from the Ludlow, in …

A genus of spiral gastropod shells, often of large size, characteristic of the lower Silurian rocks.