diff --git a/LoopProjectFile/DataCollection.py b/LoopProjectFile/DataCollection.py
index fe8d92f..695e55c 100644
--- a/LoopProjectFile/DataCollection.py
+++ b/LoopProjectFile/DataCollection.py
@@ -79,7 +79,8 @@ def CreateObservationGroup(dataCollectionGroup):
     obGroup.createDimension("foldObservationIndex", None)
     obGroup.createDimension("foliationObservationIndex", None)
     obGroup.createDimension("discontinuityObservationIndex", None)
-    obGroup.createDimension("stratigraphicObservationIndex", None)
+    obGroup.createDimension("stratigraphicObservationIndex", None)    
+    
     faultObservationType_t = obGroup.createCompoundType(
         LoopProjectFile.faultObservationType, "FaultObservation"
     )
diff --git a/LoopProjectFile/ExtractedInformation.py b/LoopProjectFile/ExtractedInformation.py
index 39a73d7..a25d6df 100644
--- a/LoopProjectFile/ExtractedInformation.py
+++ b/LoopProjectFile/ExtractedInformation.py
@@ -255,8 +255,9 @@ def GetDiscontinuityLog(root, indexList=[], indexRange=(0, 0), verbose=False):
     )
 
 
+
 # Set stratigraphic log
-def SetStratigraphicLog(root, data, append=False, verbose=False):
+def SetStratigraphicLog(root, data, thickness_calculator_data=None, append=False, verbose=False):
     """
     **SetStratigraphicLog** - Saves a list of strata in (formation,
     thickness) format into the netCDF Loop Project File
@@ -302,26 +303,56 @@ def SetStratigraphicLog(root, data, append=False, verbose=False):
             zlib=True,
             complevel=9,
         )
+        
+        # Define compound type for thickness calculator (list of length 5)
+        thicknessCalculatorType_t = siGroup.createCompoundType(
+            LoopProjectFile.thicknessCalculatorType, "ThicknessCalculator"
+        )
+        siGroup.createVariable(
+            "thicknessCalculator",
+            thicknessCalculatorType_t,
+            zlib=True,
+            complevel=9,
+        )
     else:
         siGroup = resp["value"]
 
     if siGroup:
         stratigraphicLayersLocation = siGroup.variables["stratigraphicLayers"]
+        thickness_calculator = siGroup.variables["thicknessCalculator"]
+        
         index = 0
         if append:
             index = siGroup.dimensions["index"].size
         for i in data:
             stratigraphicLayersLocation[index] = i
             index += 1
-        siGroup.setncattr("index_MaxValid", index)
+         # Write thickness calculator data (must match expected structure)
+        if thickness_calculator_data:
+            # Check that each entry is a tuple/list of length 5
+            for tc in thickness_calculator_data:
+                if len(tc) != 5:
+                    errStr = "(ERROR) Each entry of thickness calculator data must be of length 5; this one is of length " + str(len(tc))
+                    if verbose:
+                        print(errStr)
+                    return {"errorFlag": True, "errorString": errStr}
+            import numpy as np
+            # Convert the first (and only) tuple to a structured array
+            structured_data = np.array([thickness_calculator_data[0]], dtype=LoopProjectFile.thicknessCalculatorType)
+
+            # Assign only the first structured row
+            thickness_calculator[:] = structured_data[0]
+            
+            
     else:
         errStr = "(ERROR) Failed to create stratigraphic log group for strata setting"
         if verbose:
             print(errStr)
         response = {"errorFlag": True, "errorString": errStr}
+        
     return response
 
-
+    
 def GetStratigraphicLog(root, indexList=[], indexRange=(0, 0), verbose=False):
     response = {"errorFlag": False}
     resp = GetStratigraphicInformationGroup(root)
diff --git a/LoopProjectFile/LoopProjectFile.py b/LoopProjectFile/LoopProjectFile.py
index c54bef3..2ba3e14 100644
--- a/LoopProjectFile/LoopProjectFile.py
+++ b/LoopProjectFile/LoopProjectFile.py
@@ -64,11 +64,11 @@ class EventRelationshipType(enum.IntEnum):
     FAULT_FAULT_OVERPRINT = 4
 
 class ThickenessCalculatorType(enum.IntEnum):
-    ALPHA = 0
-    INTERPOLATED_STRUCTURE = 1
-    STRUCTURAL_POINT = 2
-    PLACEHOLDER_1 = 3
-    PLACEHOLDER_2 = 4
+    PLACEHOLDER_1 = 0
+    PLACEHOLDER_2 = 1
+    PLACEHOLDER_3 = 3
+    PLACEHOLDER_4 = 4
+    PLACEHOLDER_5 = 5
 
 # ###  External Accessors ### #
 
@@ -295,6 +295,15 @@ def Set(filename, element, **kwargs):
                 response = ExtractedInformation.SetStratigraphicLog(
                     root, append=True, **kwargs
                 )
+                
+                
+            ###################################
+            # ###################################
+            # elif element == "thicknessCalculator":
+            #     response = ExtractedInformation.SetThicknessCalculator(root, **kwargs)
+                
+                
+                
             elif element == "faultLog":
                 response = ExtractedInformation.SetFaultLog(root, **kwargs)
             elif element == "faultLogAppend":
@@ -739,9 +748,9 @@ def CheckFileValid(filename, verbose=False):
         ("group", "S120"),
         ("supergroup", "S120"),
         ("enabled", "u1"),
-        ("ThicknessMean", "<f8", (len(ThickenessCalculatorType)), ),
-        ("ThicknessMedian", "<f8", (len(ThickenessCalculatorType)), ),
-        ("ThicknessStdDev", "<f8", (len(ThickenessCalculatorType)), ),
+        # ("ThicknessMean", "<f8", (len(ThickenessCalculatorType)), ),
+        # ("ThicknessMedian", "<f8", (len(ThickenessCalculatorType)), ),
+        # ("ThicknessStdDev", "<f8", (len(ThickenessCalculatorType)), ),
         ("colour1Red", "u1"),
         ("colour1Green", "u1"),
         ("colour1Blue", "u1"),
@@ -751,6 +760,11 @@ def CheckFileValid(filename, verbose=False):
     ]
 )
 
+thicknessCalculatorType = numpy.dtype(
+    numpy.dtype([("name1", "S120"), ("name2", "S120"), ("name3", "S120"), ("name4", "S120"), ("name5", "S120")]),
+    "ThicknessCalculator"
+)
+
 eventRelationshipType = numpy.dtype(
     [
         ("eventId1", "<u4"),
diff --git a/LoopProjectFile/__init__.py b/LoopProjectFile/__init__.py
index e7f59a8..da33a1c 100644
--- a/LoopProjectFile/__init__.py
+++ b/LoopProjectFile/__init__.py
@@ -13,6 +13,7 @@
     foliationObservationType,
     discontinuityObservationType,
     stratigraphicLayerType,
+    thicknessCalculatorType,
     stratigraphicObservationType,
     contactObservationType,
     eventRelationshipType,