50 



APPENDIX TO THOMPSON'S VERMONT. 



TERTIARY FORMATION. 



WHITE CLAY. 



YELLOW OC'URE. IRON ORE. BROWN COAL. 



had cemented it together, has been dissolved 

 and washed out. In Havdwick, Berlin, 

 and some other places, this blue silicious 

 limestone is regularly arranged in parallel 

 strata, showing very distinctly planes of 

 deposit. But it more commonly occurs in 

 irregular beds of unequal thickness, in the 

 different varieties of slates. 



Throughout nearly the whole of what we 

 have called tlie talcose division of the state, 

 the waters are soft and very pure, but 

 those of the calcario-raica slate division are, 

 on tlie contrary, hard, being, in general, 

 strongly impregnated with lime. But the 

 i-eason is obvious ; for, in the former case, 

 there is no lime, excepting what exists in 

 the materials of tlie drift, while in the latter, 

 besides the lime in the drift, the blue sili- 

 cious limestone of the formation is diffused 

 through every part, and being, bj' exposure, 

 readily disintegrated and dissolved, keeps 

 the waters of the neighborhood constantly 

 impregnated with lime. 



The principal metalic ores found in this 

 division, are iron and copper pyrites, or 

 the sulphiirets of iron and copper. These, 

 and particularly the sulphuret of iron, are 

 found, though, for the most part, sparing- 

 ly, throughout the whole division, usually 

 in the form of small yellow cubes, Avhich 

 are not unfrequently mistaken for gold. 

 The most extensive deposits of pyrites are 

 at Strafford, Coii)ith, Woodbury and Brigh- 

 ton. That at Strafford is fully described, 

 together with an account of the manufac- 

 ture of copperas from it, in our description 

 of that town in Part III., page 167. The 

 veins of pyrites at Corinth consist of the 

 sulphurets of copper and iron in nearlj' 

 eijual proportions. In Thetford there is a 

 small vein of galena or sulpliuret of lead. 



In the different parts of this great divi- 

 sion of the state, there is found a considera- 

 ble variety of interesting minerals, most of 

 which are mentioned in Part III., under 

 the names of the tovrus in whicli they are 

 found. 



TeR'I' I ART F0R3I AT lOX. 



It has been genei-ally supposed, until 

 within a very few j'ears, that no geological 

 formation existed in Vermont, of an age 

 intermediate, between the lower silurian 

 and the drift, or post-tertiary. In otlier 

 words, it was supposed that tlie corbonife- 

 rous series, and the secondarj' and tertiary 

 formations, were entirely wanting. Still 

 it has been long known that there was a 

 series of deposits along the western foot of 

 tlie Green Mount;iius, the geological ago of 

 which was exti'cmely doubtful, and it was 

 not till the discovei-y of the deposit of Brown 

 Coal in Brandon, in 1848, that the uncer- 

 taii^y was in any degree removed. 



The deposits above mentioned, commence 

 in the south part of the state, at Benning- 

 ton, and, extending northward, have been 

 traced as far as Milton, in Chittenden 

 county ; and, probahly, will be traced still 

 further north into Canada. The material 

 in these deposits, which iirst brought tliem 

 into notice, was the brown oxide of iron, or 

 brown liematite. This iron ore has been 

 known and Avorked at Bennington, Pitts- 

 ford, Brandon and Monkton, for a great 

 number of years. 



It was also early noticed that there were 

 beds of a beautiful white clay, along the 

 same line, generally in the vicinity of the 

 broAvn iron ore. The nature of this clay 

 was little understood, but being found to 

 answer as a substitute for whiting, it was, 

 for a Avhilc, considerably used in making 

 putty for setting glass. Hence these beds 

 of clay became known as putty beds. Du- 

 ring the war with Great Britain, in 1812, 

 one of these beds in Monkton was exandued 

 l)y Prof. .1. Muzzy, who published an 

 account of it, with an analysis of the clay, 

 in the "Repository," a monthly periodi- 

 cal, published at Middlebury. He showed 

 it to be kaolm, or porcelain clay ; and 

 efforts were made, about that time, to get 

 up a manufactory of poi'celain ware. 



Subsequently, associated, for the most 

 part, Avith the beds of brown hematite, 

 were found, not only extensive beds of pure 

 yellow ochre, Ijut large quantities of the 

 ores of manganese, both of whi :ii are arti- 

 cles of mucli economical value ; and at some 

 localities in i\\Q same connexior., were also 

 found beds of very pure white quartz sand. 

 The deposits, above mentioned, along the 

 western foot of the Green JMountains, have 

 been, as already remarked, known for many 

 j^ears. But in addition to these, in sinking 

 shafts in the iron ore-bed, in Brandon, 

 about 1848, a deposit of Lignite, or Brown 

 Coal, was discovered, which has thrown 

 some light upon the geological age of the 

 deposits above described. 



Of all the localities, to which we have 

 referred, that at Brandon is the most in- 

 teresting, not only on account of the Brown 

 Coal, but oi\ account of having all the other 

 materials in conjunction with it. AVe Jiave 

 here, in the area of a few acres, the follow- 

 ing substances, which are of economical 

 vahie : 



1. Pui'e Avliite (juartz sand. 



'1. Beautiful white and stained kaolin, or 



porcelain clay. 

 ;J. YelloAv ochre. 



4. BroAvn hematitic iron ore. 



5. Ores of manganese. 

 G. BroAvn Coal. 



The tAVO Iirst, in the above list, make their 

 appearance at, or \evy near, the surface ; 



