To summarize all of the comments try this:
Option Explicit
Sub test()
Dim rng As Range
Set rng = Range("A1:B10")
Call find_max(rng)
End Sub
Sub find_max(rng1 As Range)
Dim dblM As Double
dblM = -9E+307
Dim maxCellAddress As String
Dim cell As Range
For Each cell In rng1
If IsNumeric(cell) Then
If dblM < CDbl(cell.Value) And cell.Value <> "" Then
dblM = CDbl(cell.Value)
maxCellAddress = (cell.Address)
End If
End If
Next cell
MsgBox (maxCellAddress)
End Sub
If you want to return the max cell value change it to a function like this:
Option Explicit
Sub test()
Dim rng As Range
Set rng = Range("A1:B10")
MsgBox (find_max(rng))
End Sub
Function find_max(rng1 As Range)
Dim dblM As Double
dblM = -9E+307
Dim maxCellAddress As String
Dim cell As Range
For Each cell In rng1
If IsNumeric(cell) Then
If dblM < CDbl(cell.Value) And cell.Value <> "" Then
dblM = CDbl(cell.Value)
maxCellAddress = (cell.Address)
End If
End If
Next cell
find_max = maxCellAddress
End Function