HENDERSON COUNTY. 281 



Fossils. The beds of this limestone that are found in this county, though 

 not as rich in organic remains as at other localities, furnish some interesting 

 specimens. They seem to have been deposited in a quiet ocean, where the 

 beautiful crinoid and the delicate bryozoan abounded, and considerable por- 

 tions of the limestone are thickly covered with the finely preserved skeletons of 

 these organic forms. Indeed, these waters must have teemed with animal life, 

 for not only the shales are full of their remains, but the solid limestone itself 

 is largely composed of them. Numerous fish swam these seas in those early 

 days, as the teeth and spines they have left, as a record, abundantly testify. . 



Among the fossils most common in this limestone, are the following : Spiri- 

 fer neglectus. S. Keokuk, S. lineatus, Hemipronites crenistria, Productus Wortheni, 

 P. punctatus, ZapTirentis Dalii, and an undescribed Chsetetes. Of the crinoidea 

 most worthy of mention, is the Barycrinus magnificm. Nearly all the plates of 

 a full grown individual, together with a portion of the arms and stem, I ob- 

 tained near Biggsville. It is supposed to be the largest crinoid yet found in 

 this State. 



Burlington Limestone. This formation, which underlies the Keokuk lime- 

 stone, outcrops near Dallas City, in section 36, township 8, range 7, along the 

 river bank. The quarries lie but little above the river, and are overflowed at 

 high water. Higher up in the bluff, the Keokuk beds appear. Proceeding 

 along the bluff road, there is an outcrop of the Burlington beds, near the divi- 

 ding line between sections 28 and 29, township 8, range 6. Northeast of this, in 

 sections 22 and 23, the rock again appears, and is quarried. South and east 

 of here, there are exposures of the rock in sections 24, 25 and 26 ; also in 

 sections 29 and 30, of township 8, range 5, along Dugout creek and its tribu- 

 taries. Numbers of the more common crinoids were found at these localities 

 The rock here is considerably cherty, and much of it thin bedded. The thin 

 layers, when freed from chert, furnish good material for lime, and at most of 

 the openings there are one or more layers, a foot or so thick, that afford good 

 building stone. 



Between Dugout and Honey creeks, there are no outcrops in the bluff, but 

 they commence along the latter stream, in section 12, township 8, range 6. 

 Higher up the creek, we find outcrops in abundance for six or eight miles. 

 Quarries have been opened in sections 1, 4 and 18, township 8, range 5; also 

 in section 6, township 8, range 4. The rock has been more extensively worked 

 here than on Dugout creek, and the layers are generally thicker. Blocks of 

 any desirable size, from one to two or three feet thick, may be had. Some of 

 the layers are of a yellowish-brown color, others are tinged with blue, while 

 others are nearly white, or of a light, creamy gray. 



Much assistance was rendered me by Messrs. D. Edmonds, Jas. Peasley and 

 M. Nolan, while examining this region. 

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