EUCONODONT DIVERSITY CHANGES 87Fig. 1. Constrained seriation matrix for the Laurentian shelf and marginal terranes for each of the Ordovician
time slices described in the text. Source of locality data: Oklahoma from Bauer (1994); Alabama from
Bergstrom (1990); Girvan from Bergstrom (1990); Culzean from Armstrong (2000); Tweed from Armstrong
(1997); velicuspis Chron data from Sweet & Bergstrom (1984); ordovidcus Biozone data from Nowlan &
Barnes (1981) and Radcliffe (1998). Localities have been located onshore (to the left) to offshore with
reference to palaeogeographical maps in Scotese & McKerrow (1990) and Bevins et al. (1992). Shaded boxes
indicate a presence; biofacies for generic association in Llanvin-Caradoc and velicuspis Chron have been
defined by blocks of genera in the matrix. Biofacies were allocated for ordovidcus Biozone genera based on
generic occurrences in previous time slices (see Fig. 6 and text for explanation).