Jackcl on Orthoccras. — Rucdcmann. 217 
forward by Barrande and Hyatt in which only a cicatrix was 
shown, was against its orthoceran character. The writer's in- 
terpretation of it, however, finds corroboration now in the 
recQnt discovery by Pocta of many yoimg orthoderan shells 
bearing calcified protoconchs. Whether we regard the genus 
Bactrites as nautiloid or ammonoid, it is a longicone like Or- 
thoccras and that it had a well developed, fully calcified pro- 
toconch, has been abundantly shown (Branco, the writer), in- 
deed specimens with protoconch attached are no longer uncom- 
mon occurrences. Whatever mode of life is postulated of Or- 
thoccras must be equally true of Bactrites and it is clear that 
the latter could never have been fixed at its apex. A calcified 
protoconch at once demolishes the strange structure with which 
Jaekel would prop up the Orthoccras. I am disposed to be- 
lieve there is reason to infer that while in early and primitive 
forms of Orthoccras the protoconch may have been wholly of 
conchiolin, in later forms, through acceleration or other causes, 
calcification might have set in at an initial stage. The suggestion 
that Orthoccras buried itself vertically in the mud, impresses 
me as intelligible and helpful ; that it was affixed at the sea- 
bottom seems unessential and unlikely. 
As the occurrence of vertical Orthoccras in the Oneonta 
sandstone at Oxford, N. Y., w^iich has been twice referred to 
in the foregoing, constitutes the only observed illustration of 
the presumed normal attitude of these shells, I may say that 
the interpretation suggested by Dr. Ruedemann is in approx- 
imate agreement with the other conditions wherewith the 
occurrence is involved. These bodies are highly abundant in 
a certain stratum, which lies at the outer edge of a Devonic 
fresh or brackish water lagoon where land drainage was re- 
ceived in great quantity. An excessive outflow at time of 
freshet, carrying the fresh waters beyond their proper bound- 
ary, probably would have killed outright a settlement of Or- 
thoccras buried in the littoral muds without, and have washed 
into close proximity to them remains of Amnigenia and terres- 
trial plants such as characterize the true Oneonta deposits. 
Whether such an outflow could have swept away from the 
Orthoccras settlement all mobile forms of marine life may be 
a question for determination^ but it is true that as yet no other 
trace of marine life has been found in this bed. 
