Prof. Maskelyne and Dr. Lang's Miner alogical Notes. 439 



supposed by Mr. Taylor. The stones, however, as before ob- 

 served, were not seen in the act of falling ; the dust only was 

 seen which their concussion with the earth raised into the air ; 

 and Mr. Taylor's observations seem to have been made on the 

 whole with so much intelligence as to give weight to his opinion 

 on a subject upon which a person on the spot ought to have the 

 best means of forming a judgment. 



The large stone now preserved in the Britism Museum is cer- 

 tainly one of the most interesting, as it is one of the largest of 

 existing aerolites. 



Its form, as seen from- two opposite points, is represented in 

 Plate VIII. It is difficult to define the form of so irregularly 

 shaped a mass. Two nearly opposite sides of it are comparatively 

 smooth ; the remainder is one mass of pit-marks, sharp, deep, 

 and irregular, and in two or three cases the pit-marks are deep 

 holes or fissures penetrating to some depth into the stone. The 

 crust is of a grey brown, tolerably thick, but on one of the much- 

 pitted sides presenting the aspect of a less thick coating than 

 is seen elsewhere on the aerolite, and probably indicating a sur- 

 face of disruption — perhaps the one from which the smaller 

 Parnallee stone may have been broken while the whole aerolite 

 was in its transit through the atmosphere. 



The material of the stone takes a good polish, and presents 

 a beautiful mottled surface. It is in fact a mass of spherules, 

 and though not so varied as the really marbled and veined stone 

 of Akbarpur, or the coarse breccias of Assam, Aigle, &c, it is 

 not less striking than any of these, from the peculiar character 

 imparted to its polished surface by its highly spherular structure 

 and compact nature. 



In the microscope it forms the most beautiful and instructive 

 object I have yet seen among the sections of aerolites. Like 

 Borkut in the number of its spherules, it differs from that sin- 

 gularly pisolitic stone in the compactness with which its sphe- 

 rules are compacted into a solid whole ; indeed it is probably to this 

 compact solidity of structure that we are indebted for its falling 

 in so large an unbroken mass. 



The spherules are well defined in form, and are cemented 

 together in a great degree by meteoric iron and by a considerable 

 amount of meteoric pyrites, each of which, but especially the 

 pyrites, is often, as it were, moulded round and between the 

 closely packed spherules. They are mixed, and their interstices 

 filled with a dark mineral (Hyalosiderite? or Fayalite?) in small 

 amount. The marvellous variety revealed by the microscope in 

 the structure and contents of these spherules makes a slide of 

 the Parnallee stone an aerolitic microcosm in itself. Some are 

 seen to consist of porphyritic assemblages of crystals held in a 



