Preliminary observations on the Mississippian system of northern New Mexico

Study of foss i l co l l ec t ions f rom the lower l imestone member o f the Sandia fo rmat ion in no r thern New Mex ico , wh ich h i ther to has been regarded as Pennsy lvan ian , shows that th is par t o f the sect ion is actua l l y Miss iss ipp ian. In the Sangre de Cr is to Mounta ins , the Meramec on ly may be represented, but in the San Pedro, Nac imiento , Jemez, and Sandia Moun ta ins , t he l ower ba r r en po r t i on s o f t he l imes t one s ec t i on may be o f an ea r l i e r Miss iss ipp ian age.