The deep boring at Spur . Figure 12. Pentamere sponge spicules, a, 4415-4420 feet belowsurface; b, 4320-4325 feet; tetramere, c, 4275-4280 feet; hexamere(?), d, 4305-4310 feet; tetramere, e, 4425-4430 feet; dimeres, f, 4320-4325 feet; g, 4250-4255 feet; h, 4195-4200, 4215-4220, 422&-4230,4275-4280, 4285-4290, 4330-4335, 4365-4370, 4385-4390, 4415-4420,4445-4450, 4465-4460, 4475-4480 feet. X 40. Pinnules and spines of crinoids and especially joints of the stemsof crinoids are often present in the Cisco. The pinnules are groovedon one side. An unusual form is shown in Figure 13: f. A fluted and
The deep boring at Spur . Figure 12. Pentamere sponge spicules, a, 4415-4420 feet belowsurface; b, 4320-4325 feet; tetramere, c, 4275-4280 feet; hexamere(?), d, 4305-4310 feet; tetramere, e, 4425-4430 feet; dimeres, f, 4320-4325 feet; g, 4250-4255 feet; h, 4195-4200, 4215-4220, 422&-4230,4275-4280, 4285-4290, 4330-4335, 4365-4370, 4385-4390, 4415-4420,4445-4450, 4465-4460, 4475-4480 feet. X 40. Pinnules and spines of crinoids and especially joints of the stemsof crinoids are often present in the Cisco. The pinnules are groovedon one side. An unusual form is shown in Figure 13: f. A fluted and tuberculated spine of an echinoid was noted at 4485feet. Archeocidaris? Rhombopora lepidodenroides was noted at 4165 and 4275 feet, andbetween these points, but seldom below. Other bryozoa were scarcebut not absent. One is represented in Figure 13: d, another inFigure 13: Figure 13. Jaws of annelids,* a, 4446-4450 feet below surface; b,4385-4390 feet; c, 4225-^230, 4295-4300; 4365-4370 feet; d, uniden-tified bryozoan, 4425-4430 feet; e, ditto, seen in a thin section inlimestone, in cross section, 4140-4145 feet; f, pinnule of crinoid C)4465-4470 feet. X 40. •These are now known as conodonts. The Deep Boring at Spur 83 Ambocoelia planoconvexa is believed to have been represented inthe two next to the deepest samples. Two very young specimensof a brachiopod of this type were noted. One of these is shown inFigure 14: a, in imperfect roughoutline. A valve of a shell of unknown affinities was seen in the next tothe last sample in the well. It is shown in Figure 14: i. Broken parts of chitinous jaws resembling forms ascribed toannelids were noted in a few samples. Three of these are probablyreferable to one and the same species, differing only slightly in
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