The material presented here is modern. The Jurassic part of the discussion is based mostly on published literature. We illustrate some specimens from our large collection of thin sections from Jurassic sponge reefs in Europe. However, only silicified material extracted by etching can provide the three-dimensional specimens needed for direct comparison with the Recent. To accomplish this goal, we have re-illustrated some of the material of Schmalzriedt (1991), which was loaned to us by the University of Tübingen.

Modern samples were obtained from the North Hecate Strait, the Aristazabal Island and the South Queen Charlotte Sound (Goose Island Trough) reef complexes (Table 1 and Table 2). All samples were collected inside the reefs. For the Hecate Strait complex (Figure 2), two IKU grab samples were collected. In each of these, one subcore, 9 cm in length, was split into three segments at 0-3, 3-6 and 6-9 cm depth (Table 2). In addition, sponge fragments were collected from the surface of one of the IKU grab samples (TUL99A01 "forams" sample in Table 2). Two piston cores, with associated triggerweight cores, were also obtained from the Hecate Strait complex. Both piston cores cross the mixture of sponges and trapped mud that constitute the sponge reef and reach into the underlying glaciomarine sediment. Still in the Hecate Strait reef complex, three slurp gun samples were collected by a manned mini-submersible.

In the Aristazabal Island reef, two IKU grab samples were collected, each with one 9cm subcore (no multibeam imagery is available for this location). Dead sponge fragments from the surface of one of the IKU grabs have also been investigated (TUL99A07 "forams" sample in Table 2). Six Shipek grab samples were obtained from the South Queen Charlotte Sound complex (Figure 3) while in the Strait of Georgia, one piston core and its associated triggerweight core were collected from the seafloor. The Strait of Georgia (not on Figure 1) is situated between Vancouver Island and the Canadian mainland; the core was taken at the latitude of the city of Vancouver.