34 0. a Derby—Santa Catharina Meteorite. 
metallic ee of Daubrée, or perhaps rather it should be said 
that it throws new light on the real structure of the former. 
This crust has been sbesived in two forms, which, from the 
aspect presented macroscopically, may be: called provisionally, 
the granitoid and the jog) thine Although the former has 
not, ‘like the latter, been observed adherent to the iron, it is 
evidently the primitive f form and will be described first. It 
consists essentially of olivine in small glassy crystalline frag- 
ments and of plagioclase feldspar (apparently anorthite) in 
grains up to 6 or 8 millimeters in diameter. It is traversed by 
fine veinlets of black limonite which has also stained the mass 
red so that it poo the appearance of ordinary half decom- 
fae granite. r the microscope it has the aspect of a por- 
olivine grains are beautifully clear but much fractured, showing 
along the cracks a yellow discoloration which oceasionally 
presents a beautiful botryvidal appearance. The specimens 0 
this rock have bilge teat been Nalin alee so that 
they show nothing of the original surface. They represent a 
however, a thickness of several centimeters at least. No gra 
of metallic iron have thus far been detected in them, Bak a 
points of the rock exert a slight influence on the magnetic 
_ needle, their presence is suspected. inute grains that appear — 
to be magnetite have been separated with the magnet, but — 
have not yet been examined. The porphyritic rock forms a 
crust, 1 to 2 centimeters thick, completely enveloping an oblong 
rounded mass of iron, 18 centimeters long and 10 centimeters _ 
mass, which may be called a meteoric individual, as it has — 
evidently not been broken from a larger mass since the fall, is 
that of the concretionary masses of limonite common in decom- 
posed granite and elsewhere. This is a true porphyry con- 
presence of aienocs pene cavities, and the’glass presents a 
a fluidal structure. The feldspar has much the same appear- — 
nce as in the granitoid form, that is to say, a clear nucleus — 
is 
eroauben by an opaque porti on. The nucleus, however, 
