No. 136.] 55 



The fossils of this group are numerous and very marked. 

 Corals are in great numbers, many beautiful small branched 

 forms being found in the soft shale ; some of which, showing 

 merely in dark films like pressed plants, would hardly be thought 

 corals by an ordinary observer (Fig. 15) : others, in the lime- 

 stone, are in flattened columnar masses like honeycomb ; others 

 still in rounded forms, and the structure is often so minutely 

 preserved as to be visible only with a magnifier. One very pecu- 

 liar coral is the Catenipora, the name of which, implies " chain- 

 like cavities." Its cells or tubes are oblong, and are arranged in 

 rows, so that when broken across, their section resembles the 

 series of links in a chain. This species of coral is found in the 

 same rock as far west as Louisville, Ohio ; and the same, or a 

 closely similar form, is found in strata of similar age in Northern 

 Europe. 



Half a dozen species of trilobites are found in the Niagara 

 shale; the small Calymene senaria (Fig. 16, No. 3) being scarcely 

 distinguishable from the similar form in the Trenton limestone: 

 indeed, it is not certain but that they are the same ; if so, it is 

 a very remarkable instance of the long endurance of a single 

 species. A large elongated trilobite, with the lobes of the back 

 so obscure as to be hardly perceptible, is also found (the Homa- 

 lonotus delphiiiocephalus (Fig. 1^) ; likewise the Lichas boltoni, a 

 very large and handsome species, broad in proportion to its 

 length, and with the ends of the ribs extended into points. 



Some of the most perfect crinoids known are found in this 

 rock, which (as well as its other fossils) are beautifully figured 

 in the State Palseontology of Prof. Hall. A very common one is 

 the Caryocrinus ornatus; the globular head, or body, made up of 

 many angular plates, being the part usually found, having lost 

 its stem and the jointed arms which stood on its summit (Fig. 

 18, No. 1, 2). 



A small but perfect star-fish has been found in this rock, and a 

 great variety of small brachiopodous shells abound in many of 

 its localities. All are figured in the State Palseontology. 



The next series of strata in upward succession are very deep 

 beds of shale, slate, and thin limestones, the whole of which in 

 Central and Western New- York attain the thickness of nearly a 

 thousand feet. Its lower part in Central New-York is composed 

 for several hundred feet of a soft red shale or hardened clay, 

 especially conspicuous along the canal in Madison county, Its 



