Without complicating things ... Yes, left-to-right and then top-to-bottom would be the preferred way of sorting things.
With complication ... you can actually instruct the user (and useragent) with regards to how things are sorted logically, without regards to the actual visual presentation layout.
Now, that being said ... Does the data you are listing actually follow a row and column matrix, or is it better understood as multiple sets of information that will appear on one row only to wrap to the next whenever suitable?
Perhaps a definition list would be a more suitable element? In other words -- instead of this (hypothetical data):
Something like this:
Then, for visual representation, you can always give each
ddelement a fixed size and float it left. You get the appearance of a table, but the semantics of something more suitable for the data in question.