...shale resting on the Encriniil bods is completely filled with a small Orthis or Stenfcesma (Ambnciidid umbonata). This species so abounds that in some places...matter to cause the mass to cohere." In the second Ambocodia, zone (R), described elsewhere, A. umbonata has a remarkable development. Elsewhere in the...

...shale resting on the Encrinal beds is completely filled with a small Orthi-n or Stenecesma (Amboctjelia umbonata). This species so abounds that in some places...second Ambocoelia zone (R), described elsewhere, A. umbonnta has a remarkable development. Elsewhere in the section layers an inch or less in thickness...

...shale resting on the Encrinal beds is completely filled with a small Orthis or Stenecesma (Ainbocixlia umbonata). This species so abounds that in some places...them. In actual numbers there are a great many more A. iimbonata than any other fossil. It extends from Zone A to Zone Y. Its vertical range is equally great...