J. M. Clarke—Devonian Spores. 287 
substance is compact and has a granular Appearsnes The 
external wall has one third the thickness of the s The 
interior cavity is filled with crystalline calcite. In Seeikci 
with these are many somewhat smaller and often slightly 
flattened spores, from which most of the external wall has been 
removed, leaving only a single thin carbonaceous days an 
a acdete like spot at or near the center, the calcite has, in 
crystallizing, oriented itself differently from that of the sur- 
rounding space, which leaves the impression that this spot may 
represent the original internal cavity of the spore. These bodies 
measure from one-third to one-half a millimeter in diameter, and 
are all macrospores. +c microspores have been found and no 
satisfactory evidence as yet of sporocarps. 
3. Sporangites (Protosalvinia) bilobata Dawson, 1883, 
“Sp porocarps, oval or reniform, three millimeters to six 
millimeters in diameter, each showing two rounded promi- 
nences at the ends, with a depression in the middle, and some- 
times a raised yes or isthmus at one side connecting the 
prominences. Some of the specimens indicate that each 
prominence or a arita contained several macrospores. At 
first sight it would be ony to eke these bodies for valves 
of Beyrichia,”—Dawson, op. cit. 
an examination SF boon of slices of the rock contain- 
ing these bodies, I find that they occur alone, that is unmixed, 
with the forms already describae and as far as observed, with- 
Out other fossils. 
porocarps.—T hese measure from two-thirds to one millimeter 
in greatest diawieter, being thus considerably smaller than Dr. 
awson’s specimens. In general contour and outline they are so 
mee g suggestive of Beyrichia or Primitia as certainly to 
mislead j = macroscopic characters. 
‘A Single deep pit situated mapas medially and alighiy° to 
of prominences aie three. As far as observed, opposite 
sides are symmetrical in the ddesai yg and position of the tuber- 
The substance of the sporocarps . Ng tictge oc made up of 
minute, densely set, hexagonal ce w hich, o on the surface, 
appear as hexagonal pittings Be in section as transverse 
