GEOLOGY OF DELAWARE COUNTY. 411 



Frngments of a rough, porous, silicious rock, generally very ferruginous, pro- 

 vincially termed '• Honeycomb stone," are found strewed around this serpentine. 

 Fragments of this unsightly rock are associated with all our develoi)ments of 

 serpentine of any extent, and as they are found in the greatest profusion around 

 the serpentine district of Middletown, the rock will be described in connection 

 with that tract. 



The minerals of the serpentine will be given in the general catalogue of the 

 minerals of the Countj', but it may be remarked that in the noitheastern part of 

 the exposure under consideration, magnetic iron ore is found in considerable 

 quantities, apparently intersfratified with the serpentine rock. In the same 

 vicinity the serpentine is of a more magnesian character. 



Proceeding southwesterly towards Crura Creek, the true serpentine disappears, 

 but the talcose strata are extended, and can be traced for a considerable dis- 

 tance in the direction of the " Blue Hill' serpentine in Upper Providence. It 

 is in this extension that some of these strata assume a more steatitic character, 

 but no soapstone has been found of a quality sufficiently good to be quarried 

 for the uses to which this material is generally applied. Thin strata of a green 

 colored talcose slate sometimes alternate with the mica slate of this vicinity. 



The exposure of serpentine known as '• Blue Hill " is not large, but at the 

 point specially bearing that name, the rock does not present itself in any ques- 

 tionable shape. If any part of the rock near Morgan's Corner can be regarded 

 as " true injected iyncoits serpentine" the plutonic origin of the serpentine at 

 Blue Hill cannot be doubted. The rock is very much divided by seams, some 

 of which are tilled with amianthus. 



The next exposure of serpentine in order is the large tract in Middletown. It 

 is the largest develoi)ment of this rock in the County, and particularly so in its 

 dimensions across the regular strata of that district. AVhere it is exposed or 

 approaches the surface very nearly, it constitutes what is known as the '' Bar- 

 rens " of Middletown, 



The "Honeycomb" stones before mentioned are spread around this serpentine 

 in rather inconvenient profusion. Their origin has been a matter of wonder, as 

 they have not been found in place, but are always seen scattered about as a kind 

 of out-liers on the flanks of the serpentine. Their appearance in many instances 

 resemble the slag of a furnace, and if we cannot conclude that they have resulted 

 from the metamori)hism of a ferro-silicious stratum of rock b}' the application of 

 a high degree of heat, accompanied by the emission of gaseous matter, would it 

 be unreasonable to regard them as the slag thrown otf from the surface of a 

 mass of melted serpentine? The apparent laminated structure of some of these 

 fragments of " Honeycomb stone " favor the former theory, but furnace slmjs fre- 

 quently exhibit the same ajjpearance. It will therefore be safest to regard them 

 as the vitreous slag of a melted mass of serpentine, until they shall have been 

 discovered in situ ; and that too in connection with strata of a proper compo- 

 sition, that by their metamorphism, would result in Uoneijcomh rock. 



The Middletown serpentine is noted for the large amount of chrome it has 

 afforded. Large quantities have been obtained here within a few years past. It 

 is procured in two ways, by mining, or by washing* the alluvial sand of the beds 

 of streams that have passed through the serpentine. The latter is preferred, as 

 the mineral is then obtained in its purity. When obtained in this state, it has 

 the ai)pearance of a shiny black sand, nearly every particle of which when 

 brought under a glass is shown to be a perfect crystal. 



Beyond the serpentine proper of this district, the accompanying talcose or 

 magnesian strata extend to Chester Creek, towards which they are very much 

 decomposed. 



• Most of this grain chrome is found iu the ancient beds of streams mixed with sand and 

 gravel. These deposits are discovered in various ways, and when found, the soil and superin- 

 cumbent clay are removed, and the whole material of the deposit is thrown into strong iron sieves 

 which are worked by hand under water. The sand and chrome grain pass through the sieve 

 and are deposited in the vessels containing the water The contents of the.se vessels are then re- 

 moved to the " wash-house," where troughs are provided, through which water is caused to p;iss 

 with considerable velocity. In these troughs, which have stops in them to create a ripple, the 

 saud is washed out from the chrome grain, having a much less specific gravtiy. The washing 

 has to be repeated three times before the ore is ready to be dried and packed in barrels for the 

 manufacturer. 



