124 



Fig. 



Amplexus ijamiltoxll. Hall. 

 (Fig. 5.) (111. Dev. Foss., PL 

 XIX.) 



Distinguishing Characters. — Elon- 

 gated cylindrical, gently tapering 

 form, often abruptly bent at the 

 base: strongly wrinkled epitheca; 

 comparatively slight development 



,. 5. Amplexus hamiltonioe. ,. . . , . . 



Front and side view of a specimen < >i septa: well-uevelo] >e< I tabula?, 

 from Morse Creek, showing irregular 



form, discontinuous septa and cen- bent down near the thill wall, 

 tral tabulae. The center of the 



calyx is broken. Natural size. Stud. Found frenueiltlv ill the Moscow 



Pal. Coll. Harv. Univ. Cat. No 841. ruuuu n t queni i f \ in nit ^himim\ 



anginal.) shale, three to five feet above its 



base, between Sections 4 and 5, and at Morse Creek. 



Amplexus (?) intermittens.* Hall. (Fig. 6.) (111. Dev. 

 Foss.. PL XXXII., Figs. 8-13.) 



Distinguishing Characters. — Small size; irreg- 

 ular form, varying from cylindrical, with sud- 

 den expansions, to regularly conical outline; 

 well-developed septa, which reach to the center, 

 and frequently unite before reaching it. 



Found in the lower Moscow shale, between 

 Sections 4 and 5. It is comparatively rare. 



Fig. 6. Am- 

 plexus (?) in- 

 termittens (af- 

 ter Hall). 



Genus HELIOPHYLLUM. Hall. 

 [Ety. : Helios, sun ; phylUm, leaf.] 

 ( Dana's Zoophytes, 1848, p. 856.) 

 Simple or compound, the individuals conical, or turbinate, 

 with shallow calyx, and surrounded by a thin epitheca. 

 Septa alternating- in length, the longer extending to the 

 center, all supplied with supporting lamellae, which curve 

 from the periphery upwards and inwards, so as to describe 

 a convex npward-cnrve. and appear in the calyx as cross- 

 bars or carina'. 



Heliophyllum halli: E. and H. (Fig. 7.) (111. Dev. 

 Toss.. PI. XXIII.) 



* This species is probably not an Amplexus, nor does it seem to belong to any described 



genUS. 



