His oyster table stood at the lower end of the room, which was in constant use twice a day all the year round (Source)
What is this lower? Does this mean it is sunk? But it doesn't make sense.
If the dwelling was a hut with a dirt floor, the 'lower end' could be physically lower. Here, the dwelling is a proper building, so the lower end is probably the less formal end, away from the door/window/important furniture (note that there's a desk, bible and book of martyrs at the 'upper end' of the room).
The only example I found is here, in a travel review.
(EDIT: PS I often tell my students not to worry about every detail of specific meaning when the general meaning is clear. In this sentence, the room clearly has two ends, with the oyster table at one end and the desk at the other. On the other hand, it is good that you are reading carefully, that you want to understand and that you are asking questions.)