Geology and Mineralogy. 267 
continuous eyelobes; the important family of the Ptychoparida 
is absent; the genera Conocoryphe, Microdiscus and Olenellus 
are absent. He further remarks: “This fauna is distinguished 
from that of Olenellus by two marked features. It is more primi- 
tive and also more pelagic. The way in which the trilobites are 
bound together by a single feature of a continuous eyelobe shows 
a unity of origin and a closer relationship than is found in the 
trilobites of any other fauna, and yet among these trilobites there 
are forms which in other respects are parallel to the types which 
developed in the later faunas. Thus in Protolenus we have the 
flat pleura, with the diagonal furrow of Paradowxides, but in sub- 
gen. Bergeronia the deeply-grooved, geniculated pleura of Ptycho- 
paria, and at the same time the prominent glabella and deep 
dorsal furrows of Solenopleura. Micmacca, as has already been 
said, predicates Zacunthoides of a later fauna. Finally, Proto- 
graulos, in its almost obliterated glabella and flat cephalic shield, 
recalls Agraulos and Holocephalina of the Paradoxides fauna. 
It is a more pelagic fauna than that of Olenellus, for we notice 
the absence of many forms of the Olenellus fauna that were dif- 
ferentiated for shore-conditions. Trilobites with fixed outer 
checks, like Olenellus and Microdiscus, are absent; calcareous 
corals and sponges are rare, and no Lamellibranch is known. On 
the other hand, Foraminifera are quite common in some layers, 
and the Gasteropods are mostly such as were adapted for com- 
paratively deep water.” 
Although the evidence is not conclusive that the fauna lived 
before the Olenellus fauna, it is without doubt a different fauna. 
The two faunas may have been contemporaneous, the author 
observes, the Protolenus fauna being adapted to deeper and 
quieter waters than the other. In this case ‘we would expect,” 
he writes, “that at a locality where the two faunas occurred in 
succession in a series of deposits, the Olenellus fauna would be 
found beneath that of Protolenus,” and he expresses the opinion 
that assises 4 and 5 (of the Hanford brook section) |this fauna 
occurring chiefly in assises 2 and 3] show no trilobite fauna and 
* this seems the more probable place for the Olenellus fauna, see- 
ing that while this fauna has several genera of trilobites in com- 
mon with the Paradoxides fauna, it has but two that are found 
in the Protolenus fauna.” | H. S. W. 
2. Pre-Cambrian organisms.—L. Cayeux has recently pub- 
lished* a preliminary note on the existence of numerous remains 
of Sponges in the pre-Cambrian schists of Brittany, thus adding 
to the known organisms of this early fauna.+ The evidence is in 
the form of pyritized sponge spicules of which the original form 
* “De l’existence de nombreux débris de Spongiaires dans le Précambrian de 
Bretagne,” par L. Cayeux; Ann. Soc. Géoi. du Nord., vol. xxiii, 1895, pp. 52-64, 
June, 1895. 
+‘‘Sur la présence de restes de Foraminiféres dans les terrains précambriens 
de Bretagne. OC. R. Ac. Sc., t. exviii, pp. 1433-1435 et Ann. Soc. Géol. du Nord, 
vol. xxii, pp. 116-119. See also Bull. Soc. Géol., Fr., 3° Série, t. xxii, pp. 197- 
228, pl. xi (1894). 
