280 The American Geologist. no\ ember, i89a 
raent of the ealcite crystals. But even in quite delicate sections 
the calcareous substance, both of the nucleus and of the shells, 
is interrupted by scattered, minute granules. If we dissolve the 
section cautiously and slowly in very dilute acid, the granules 
remain behind exactly in their original position, and we recognize 
in them the dead and crumpled Ghrocapiia cells. 
The 0()lites of the (ireat Salt lake are, therefore, indubitably 
the product of lime-secreting fission-algiie, and their formation is 
proceeding day by day. The rods and tubercles are of like con- 
stitution, save that in the latter the regular concentric structure 
of the lime is lacking. Furthermore, the little rods appear to be 
richer in alga-cells than the oolites. It must be left to the Amer- 
ican botanists to accurately trace this process of oolite-forming 
in place, or at least in living material. 
But even now the observations communicated suffice for find- 
ing an explanation of the origin of a few other already long 
known oiilites. 
A few years since. Job. Walther (li w. ](» Bd. Abh. siichs. 
Ges. Wissensch. 1888 und 1891) described and indicated as a re- 
cent formation, oolites from the strand of the Red sea. A prin- 
cipal role is ascribed to deca3'ed animals. Last year 1 likewise 
investigated these oolites in place and found that they are a very 
widely distributed phenomenon along the west coast of the Sinai 
peninsula and usually decrease in frequency toward the interior 
of the land, although they still may be met with many kilome- 
ters, even days marches, distant from the shore. But the}' also 
occur in older deposits which belong to the Quaternar}' period 
and build up the subaerially formed low coastal tracts in the fur- 
ther environs of Suez, whence Bauerman described them very 
well in 18G8. They are there frequently consolidated into a hard, 
oolitic limestone. 
These oiUites are distinguished from those of the Great Salt 
lake chiefly in the fact that their nucleus always consists of a for- 
eign sand-grain. The concentric shell-structure is very conspic- 
uously less developed than the radial. Then there are alwa3's 
to be noticed in the shells, peculiar vermiform and, not rarely, 
dichotomously branching canals that are filled up with calcite, 
which, however, in its orientation is quite independent of that of 
the calcite in the concentric shells, and has a much coarser grain. 
If we dissolve the lime with acid, there remain here also minute 
