58 



APPENDIX TO THOMPSON'S VERMONT. 



INFUSORIAL SILICA. 



POPl'LATIOX OF VEEMOXT — SEVENTH CENSUS. 



CLAY STONES. 



Infusorial Silica. 



Several deposits are met with in ditterent 

 parts of tlie state, -whicli, in their situation 

 and appearance, rery mucli resemble shell- 

 marl, but instead of being, like that sub- 

 stance, calcareous, are a fine siliceous earth. 

 By examination , under the microscope, this 

 earth is found to have originated from tlie 

 flinty shell of infusorial animalcules, in the 

 same mannei' that the marl was formed from 

 the calcareous sliells of molluscs, and hence 

 it received tlie name of Infusorial Silica. 



The most extensive deposit of infusorial 

 silica, known in the state, is in Hosmer's 

 pond, in the south^vestern corner of Pea- 

 cham. This pond is surrounded by granite 

 hills, and covers about 250 acres. The in- 

 fusorial deposit is thought to average about 

 six inches in depth, over the bottom of 

 about two-thirds of the pond. When taken 

 out and dried in lum])s, it is a very good 

 substitute for clialk. When dried and ijul- 

 verised,itresembles calcined magnesia ; and, 

 hence, the pond is called, sometimes Chalk 

 pond, and sometimes Magnesia pond. 

 There is another small deposit of infusorial 

 silica, in Maidstone, in Essex county. 



By the examination of specimens of the 

 silica, from these deposits, by Prof Bailey, 

 of West Point, the shields of more tlian 

 twenty distinct species of animalcules, were 

 discovered in it Some of these ai-e so ex- 

 ceedingly minute, that, incredible as it may 

 seem, it would require a million of them to 

 make the bulk of a single mustard seed. 

 By the lalsors of Ehrenberg, and othei's, 

 these microscopic fossils have all been ar- 

 ranged, described and figured, so far as 

 known, and many of the forms are exceed- 

 ingly beautiful. I give, below, the figures 

 of a few of the many species found in Hos- 

 mer's pond. Their areas are magnified in 

 the cuts, about 73,000 times. ' 



Clay Stones. 

 Concretions of various kinds are found in 

 Vermont, but the most common are those 

 found in beds of clay, and generally known 

 by the name of Clay Stones. These clay 

 stones exhibit an almost infinite variety of 

 forms. Many of them appear as if skilfully 

 turned in a lathe, or beautifully carved by 

 art ; and lience they are every where re- 

 garded as objects of curiosity. Their most 

 common form is that of a convex lens, or 

 flattened sphere ; but various forms are 

 often blended together, in the most gro- 

 tesque and fanciful manner. At some 

 localities, they are found in the form of a 

 perfect ring, like the ring of an ox-yoke, 

 both in form and size. Those concretions, 

 which abound in the Lawrencian formation, 

 in the neighborhood of Lake Cliamplain, 

 are generally cylindrical, having their 

 longer axis nearly perpendicular to the 

 stratification of the clay, and prolonged 

 through several of the strata. These cylin- 

 drical concretions are all formed of concen- 

 tric layers around the axis of the cylindei-, 

 v/hich axis is a capillary opening, extending 

 through its whole length. They appear as 

 if they had been formed around fibrous 

 roots, which liad afterwards decayed out, 

 leaving a small perforation, like a pith, ex- 

 tending through their whole length.* Local- 

 ities of clay stones and other interesting- con- 

 cretions exist in various parts of the state, 

 and are too numerous to be particularized. 



•• Having an opporUiuity, in 1851. li examine the 

 Crag formations in the east part of E.ij;l:i.nd, I satis- 

 Hed myseir that the, go called, coprolites, which 

 abound there, and are so liighly prized and exten- 

 sivi,'ly used as a fertilizer, are, for the most part, at 

 least, concretions formed in the same manner as those 

 above named. They differ in the materials of which 

 they are cnmposed, but do not, apparently, differ in 

 the manner, in \vhich they are formed 'While ours 

 contain carbonate of lime, those found in the Crag, in 

 England, are said to consist ol' 65 per cent, of the 

 phosphate of lime, and hence the great value of the 

 latter as a fertilizer. The clay in which those con- 

 cretions were found, had probably abounded in fossil 

 bones, and the decomposition of these bones furnish- 

 er! the lime, in the condition of a phosphate, for the 

 formation cf the concretions. Thousands of tons of 

 these concretions are said to be, ammally, separated 

 from tlie Crag, and 'used as a manure. 



POPULATION OF VERMONT. 



Tiiere have now been seven complete enumerations of the inhabitants of Vermont, 

 since the organization of her government. The i-esult of six of these are given, by towns, 

 in Part II. , page 20U. The result of the seventh is given below. 



Population of Vermont i\ IS.jO. 



Towns. 

 Addison, 

 Albany, 

 Alburgh, 



Pop. 



12?. 

 1052 



1568 



Pop. I Towns. 



Pop. I Towns 



Andover, 725 Averill, 7 Bakersfield, 



Arlington, 10841 Avery's Gr., F.C. 48 Baltimore, 



Athens, SSOlBuell's Gore, 18|Barnard, 



Pop^ 



T523 



124 



1647 



