The Mark of Kri is an action game, for the PS2.
This Game uses multiple file headers and sub-headers for the files contained within the DEMO.WAD archive.
There the are several different but related 3d formats that this game uses.

The PSR header is used in PST files to represent chunks of 3d data. It is used to define level terrain.
Each PSR will begin at an offset that ends in 0.

Right After
02 C0 XX 68
are XX arrays of Vertexes:
verX, verY, verZ
What follows in Each PSR is not the same for each, but there will be a
?? C0 XX 6E somewhere after the Vertexes. It can also be the case that there are more than one vertex array in a PSR.

Another format header is BLS
There is just one BLS header in the 50 MB data file on the Winter 2002 Jampack demo.
BLS files closely resemble a file format used in Turok Evolution.

In each BLS there are chunks of 32byte arrays consisting of Vertexes and Floats:

verX, verY, verZ, 00 00 00 00
norX, norY, norZ unknown4byte float

Still another format header is MOD
These files have the header begin at an offset that ends in 8

Right after:
02 C0 XX 68
are XX arrays of Vertexes:
verX, verY, verZ,
What follows shortly afterwards but not in a set position are the unit Sphere normals:
?? C0 XX 68
norX, norY, norZ
Then somewhere shortly after are
?? C0 XX 6E
XX amount of 4 byte vertex colors:
RED, GREEN, BLUE, 80
Possibly followed somewhere afterwards by:
?? C0 XX 63:
XX arrays of UV texture coordinates:
texX, texY