126 



tube is certainly present, and the lateral tubes spring from it, and not from one another, as I 

 was at first led to believe by my examination of casts from the Corniferous. The arrangement 

 of the lateral tubes also is more variable than I had imagined. Sometimes they are entirely 

 produced from one side of the tube (Fig. 57 b) ; but at other times they are biserial and alter- 

 nate regularly with one another (Fig. 57 c). The fossil differs from the typical species of Aulo- 

 pom in the great proportionate length of the lateral buds, and in their regular and more or 

 less symmetrical method of growth, and more especially in the fact that the apertures of the 

 tubes open in the plane of growth of the entire corallum, and are neither elevated above the 

 general surface, nor perceptibly expanded. 



The only species of Aulopora to which it has any affinity is A. filiformis (Billings), but 

 this is a much more robust species, with larger tubes, and much more irregular method of 

 growth, and apertures generally distinctly elevated above the general surface. 



As occurring in the Corniferous Limestone, Aulopora (?) Canadensis is found chiefly 

 growing on the epitheca of Fistulipora Canadensis, and Diphyphyllum arundinaceum. In the 

 Hamilton Formation, it affects chiefly Heliophyllum Halli and Cystiphyllum vesiculosum, and in 

 both groups it is commonly accompanied by Spirorbis omphalodes. 



Locality and Formation. Corniferous Limestone, Port Colfeorne, and Lot 6, Concession 

 1, Wainfleet. Hamilton Formation, Bartlett's Mills, near Arkona, Township of Bosanquet. 



158. SYRINGOPORA INTERMEDIA (Nicholson). 



Corallum lax, spreading, increasing by the production of lateral buds. Corallites cylin- 

 drical, often more or less crooked, having a diameter of from one line to a line and a half, or 

 rarely two lines, the lateral buds being produced at angles of from 90 to 40, and at intervals 

 of from two to four lines. No connecting horizontal processes between the corallites, but 

 sometimes abortive spines or nodes. Epitheca with fine encircling strise, and irregular growth- 

 swellings and geniculations. Internal structure, of infundibuliform tabulae. 



In its form and mode of growth, this form agrees altogether 

 with Syringopora nobilis (Billings), of which I at first believed it to 

 be simply the young. The latter, however, is a much larger form, its 

 corallites having an average diameter of three lines, and sometimes 

 as much as five lines, and its buds being produced at longer intervals. 

 S. intermedia, on the other hand, occurs in the Hamilton formation 

 (S. nobilis being a Corniferous species), and though it is very abund- 

 ant, I have never seen any example with a diameter exceeding two 

 lines, the majority of specimens having a diameter of little over one 

 PlG 58 line. The corallites also are much more crooked and irregular, and 



fragments of Syringopora inter- the branches are produced at much shorter intervals. Some speci- 

 inedia (Nich.) natural size. From mens do not exhibit the internal structure, and these present a 



resemblance to Aulopora cornuta (Billings), from which, however, 



they are readily distinguished by not being creeping or parasitic. Upon the whole, S. interme- 

 dia appears to me to be distinguished by characters of specific value. 



Locality and Formation. Common in the Hamilton Formation, Widder ; and Bartlett's 

 Mills, near Arkona, Township of Bosanquet. 



159. AMBOCCELIA TJMBONATA (Conrad). 



Orthis umbonata (Conrad), Journ. Acad. Nat. Science, Philadelphia, Vol. VIII., p. 264, 

 PI. XIV., Fig. 21. 



. Amboccelia umbonata (Hall), Thirteenth Report on the State Cabinet, p. 71. 



Orthis nucleus (Hall), Geol. Rep. Fourth Dist., New York, p. 180. 



Amboccelia umbonata (Hall), Pal. N. Y., Vol IV., p. 269, PI. XL1V., Figs. 718. 



Since the portion of this Report treating of the Brachiopoda was written, I have come 

 across two or three unmistakable examples of the ventral valve of this little shell, which if not 

 identical with Spirifera Urii (Fleming), [ P. unguiculus, Phillips], is certainly very close to it. 

 Our specimens are from the Corniferous Limestone, a formation in which they do not appear 

 to have been detected by Hall, and I am chiefly concerned to notice their occurrence for the 

 purpose of repeating that they are entirely distinct from Productella Enensis (Nich.), to which 



